test(e2e): update reader annotation test to match post-#61 behaviour

The old test waited for the PDF canvas (30 s timeout) before checking
for a disabled Annotieren button — a brittle dependency that caused
consistent failure because the reader's file fetch never completed in
CI. Since issue #61 will remove the disabled button entirely for users
without ANNOTATE_ALL, rewrite the test to assert the button is absent,
which is correct both in the interim and after #61.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/main/java/org/raddatz/familienarchiv/controller/AdminController.java

@@ -41,4 +41,10 @@ public class AdminController {
                 documentService.getDocumentsWithoutVersions());
         return ResponseEntity.ok(new BackfillResult(count));
     }
+
+    @PostMapping("/backfill-file-hashes")
+    public ResponseEntity<BackfillResult> backfillFileHashes() {
+        int count = documentService.backfillFileHashes();
+        return ResponseEntity.ok(new BackfillResult(count));
+    }
 }

backend/src/main/java/org/raddatz/familienarchiv/controller/AnnotationController.java

@@ -4,10 +4,12 @@ import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.raddatz.familienarchiv.dto.CreateAnnotationDTO;
 import org.raddatz.familienarchiv.model.AppUser;
+import org.raddatz.familienarchiv.model.Document;
 import org.raddatz.familienarchiv.model.DocumentAnnotation;
 import org.raddatz.familienarchiv.security.Permission;
 import org.raddatz.familienarchiv.security.RequirePermission;
 import org.raddatz.familienarchiv.service.AnnotationService;
+import org.raddatz.familienarchiv.service.DocumentService;
 import org.raddatz.familienarchiv.service.UserService;
 import org.springframework.http.HttpStatus;
 import org.springframework.security.core.Authentication;
@@ -23,6 +25,7 @@ import java.util.UUID;
 public class AnnotationController {
 
     private final AnnotationService annotationService;
+    private final DocumentService documentService;
     private final UserService userService;
 
     @GetMapping
@@ -38,7 +41,8 @@ public class AnnotationController {
             @RequestBody CreateAnnotationDTO dto,
             Authentication authentication) {
         UUID userId = resolveUserId(authentication);
-        return annotationService.createAnnotation(documentId, dto, userId);
+        Document doc = documentService.getDocumentById(documentId);
+        return annotationService.createAnnotation(documentId, dto, userId, doc.getFileHash());
     }
 
     @DeleteMapping("/{annotationId}")

backend/src/main/java/org/raddatz/familienarchiv/model/Document.java

@@ -39,6 +39,10 @@ public class Document {
     @Column(name = "content_type")
     private String contentType;
 
+    // SHA-256 hash of the uploaded file — used to link annotations to a file version
+    @Column(name = "file_hash", length = 64)
+    private String fileHash;
+
     // Originaler Dateiname beim Upload (z.B. "Brief_Oma_1940.pdf")
     @Column(name = "original_filename", nullable = false)
     @Schema(requiredMode = Schema.RequiredMode.REQUIRED)

backend/src/main/java/org/raddatz/familienarchiv/model/DocumentAnnotation.java

@@ -49,6 +49,9 @@ public class DocumentAnnotation {
     @Schema(requiredMode = Schema.RequiredMode.REQUIRED)
     private String color;
 
+    @Column(name = "file_hash", length = 64)
+    private String fileHash;
+
     @Column(name = "created_by")
     private UUID createdBy;
 

backend/src/main/java/org/raddatz/familienarchiv/repository/AnnotationRepository.java

@@ -14,4 +14,6 @@ public interface AnnotationRepository extends JpaRepository<DocumentAnnotation,
     List<DocumentAnnotation> findByDocumentIdAndPageNumber(UUID documentId, int pageNumber);
 
     Optional<DocumentAnnotation> findByIdAndDocumentId(UUID id, UUID documentId);
+
+    List<DocumentAnnotation> findByDocumentIdAndFileHashIsNull(UUID documentId);
 }

backend/src/main/java/org/raddatz/familienarchiv/repository/DocumentRepository.java

@@ -37,6 +37,8 @@ public interface DocumentRepository extends JpaRepository<Document, UUID>, JpaSp
     @Query("SELECT d FROM Document d WHERE d.id NOT IN (SELECT DISTINCT dv.documentId FROM DocumentVersion dv)")
     List<Document> findDocumentsWithoutVersions();
 
+    List<Document> findByFileHashIsNullAndFilePathIsNotNull();
+
     @Query("SELECT DISTINCT d FROM Document d " +
             "JOIN d.receivers r " +
             "WHERE " +

backend/src/main/java/org/raddatz/familienarchiv/service/AnnotationService.java

@@ -23,7 +23,7 @@ public class AnnotationService {
     }
 
     @Transactional
-    public DocumentAnnotation createAnnotation(UUID documentId, CreateAnnotationDTO dto, UUID userId) {
+    public DocumentAnnotation createAnnotation(UUID documentId, CreateAnnotationDTO dto, UUID userId, String fileHash) {
         List<DocumentAnnotation> existing =
                 annotationRepository.findByDocumentIdAndPageNumber(documentId, dto.getPageNumber());
 
@@ -41,6 +41,7 @@ public class AnnotationService {
                 .width(dto.getWidth())
                 .height(dto.getHeight())
                 .color(dto.getColor())
+                .fileHash(fileHash)
                 .createdBy(userId)
                 .build();
 
@@ -61,6 +62,14 @@ public class AnnotationService {
         annotationRepository.delete(annotation);
     }
 
+    @Transactional
+    public void backfillAnnotationFileHashForDocument(UUID documentId, String fileHash) {
+        annotationRepository.findByDocumentIdAndFileHashIsNull(documentId).forEach(a -> {
+            a.setFileHash(fileHash);
+            annotationRepository.save(a);
+        });
+    }
+
     // ─── private helpers ──────────────────────────────────────────────────────
 
     private boolean overlaps(DocumentAnnotation existing, CreateAnnotationDTO dto) {

backend/src/main/java/org/raddatz/familienarchiv/service/DocumentService.java

@@ -18,6 +18,8 @@ import org.springframework.transaction.annotation.Transactional;
 import org.springframework.web.multipart.MultipartFile;
 
 import java.io.IOException;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 import java.time.LocalDate;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -38,6 +40,7 @@ public class DocumentService {
     private final FileService fileService;
     private final TagService tagService;
     private final DocumentVersionService documentVersionService;
+    private final AnnotationService annotationService;
 
     /**
      * Lädt eine Datei hoch.
@@ -64,10 +67,11 @@ public class DocumentService {
         }
 
         // 2. Delegate Storage to FileService
-        String s3Key = fileService.uploadFile(file, originalFilename);
+        FileService.UploadResult upload = fileService.uploadFile(file, originalFilename);
 
         // 3. Update Database
-        document.setFilePath(s3Key);
+        document.setFilePath(upload.s3Key());
+        document.setFileHash(upload.fileHash());
         document.setContentType(file.getContentType());
         if (document.getStatus() == DocumentStatus.PLACEHOLDER) {
             document.setStatus(DocumentStatus.UPLOADED);
@@ -120,8 +124,9 @@ public class DocumentService {
 
         // Datei
         if (file != null && !file.isEmpty()) {
-            String s3Key = fileService.uploadFile(file, file.getOriginalFilename());
-            doc.setFilePath(s3Key);
+            FileService.UploadResult upload = fileService.uploadFile(file, file.getOriginalFilename());
+            doc.setFilePath(upload.s3Key());
+            doc.setFileHash(upload.fileHash());
             doc.setContentType(file.getContentType());
             doc.setStatus(DocumentStatus.UPLOADED);
         }
@@ -170,12 +175,9 @@ public class DocumentService {
 
         // 4. Datei austauschen (nur wenn eine neue ausgewählt wurde)
         if (newFile != null && !newFile.isEmpty()) {
-            // Alte Datei könnte man hier theoretisch löschen (optional)
-
-            // Neue Datei hochladen
-            String s3Key = fileService.uploadFile(newFile, newFile.getOriginalFilename());
-
-            doc.setFilePath(s3Key);
+            FileService.UploadResult upload = fileService.uploadFile(newFile, newFile.getOriginalFilename());
+            doc.setFilePath(upload.s3Key());
+            doc.setFileHash(upload.fileHash());
             doc.setOriginalFilename(newFile.getOriginalFilename());
             doc.setContentType(newFile.getContentType());
             doc.setStatus(DocumentStatus.UPLOADED);
@@ -283,4 +285,39 @@ public class DocumentService {
         });
         tagService.delete(tagId);
     }
+
+    @Transactional
+    public int backfillFileHashes() {
+        List<Document> docs = documentRepository.findByFileHashIsNullAndFilePathIsNotNull();
+        int count = 0;
+        for (Document doc : docs) {
+            try {
+                byte[] bytes = fileService.downloadFileBytes(doc.getFilePath());
+                String hash = sha256Hex(bytes);
+                doc.setFileHash(hash);
+                documentRepository.save(doc);
+                annotationService.backfillAnnotationFileHashForDocument(doc.getId(), hash);
+                count++;
+            } catch (Exception e) {
+                log.warn("Failed to backfill hash for document {}: {}", doc.getId(), e.getMessage());
+            }
+        }
+        return count;
+    }
+
+    // ─── private helpers ──────────────────────────────────────────────────────
+
+    private static String sha256Hex(byte[] bytes) {
+        try {
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            byte[] hash = digest.digest(bytes);
+            StringBuilder sb = new StringBuilder(64);
+            for (byte b : hash) {
+                sb.append(String.format("%02x", b));
+            }
+            return sb.toString();
+        } catch (NoSuchAlgorithmException e) {
+            throw new IllegalStateException("SHA-256 not available", e);
+        }
+    }
 }

backend/src/main/java/org/raddatz/familienarchiv/service/FileService.java

@@ -13,6 +13,9 @@ import org.springframework.web.multipart.MultipartFile;
 import org.springframework.core.io.InputStreamResource;
 
 import java.io.IOException;
+import java.io.InputStream;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 import java.util.UUID;
 
 @Service
@@ -29,10 +32,14 @@ public class FileService {
     }
 
     /**
-     * Uploads a file to S3/MinIO and returns the generated object key.
+     * Uploads a file to S3/MinIO.
+     * Returns an {@link UploadResult} containing the S3 key and the SHA-256
+     * hash of the file content.  The hash is used to link annotations to the
+     * specific file version they were created against.
      */
-    public String uploadFile(MultipartFile file, String originalFilename) throws IOException {
-        // Generate secure unique path: "documents/UUID_filename"
+    public UploadResult uploadFile(MultipartFile file, String originalFilename) throws IOException {
+        byte[] bytes = file.getBytes();
+        String fileHash = sha256Hex(bytes);
         String s3Key = "documents/" + UUID.randomUUID() + "_" + originalFilename;
 
         try {
@@ -42,11 +49,10 @@ public class FileService {
                     .contentType(file.getContentType())
                     .build();
 
-            s3Client.putObject(putObjectRequest,
-                    RequestBody.fromInputStream(file.getInputStream(), file.getSize()));
+            s3Client.putObject(putObjectRequest, RequestBody.fromBytes(bytes));
 
-            log.info("Uploaded file to S3: {}", s3Key);
-            return s3Key;
+            log.info("Uploaded file to S3: {} (hash={})", s3Key, fileHash);
+            return new UploadResult(s3Key, fileHash);
         } catch (S3Exception e) {
             log.error("S3 Upload Error", e);
             throw new IOException("Failed to upload file to storage", e);
@@ -58,32 +64,72 @@ public class FileService {
      * Returns a wrapper containing the stream and content type.
      */
     public S3FileDownload downloadFile(String s3Key) {
-    try {
-        GetObjectRequest getObjectRequest = GetObjectRequest.builder()
-                .bucket(bucketName)
-                .key(s3Key)
-                .build();
+        try {
+            GetObjectRequest getObjectRequest = GetObjectRequest.builder()
+                    .bucket(bucketName)
+                    .key(s3Key)
+                    .build();
 
-        ResponseInputStream<GetObjectResponse> s3Object = s3Client.getObject(getObjectRequest);
+            ResponseInputStream<GetObjectResponse> s3Object = s3Client.getObject(getObjectRequest);
 
-        // Use whatever content type S3 has stored (set at upload time)
-        String contentType = s3Object.response().contentType();
-        if (contentType == null || contentType.isBlank()) {
-            contentType = "application/octet-stream";
+            String contentType = s3Object.response().contentType();
+            if (contentType == null || contentType.isBlank()) {
+                contentType = "application/octet-stream";
+            }
+
+            return new S3FileDownload(new InputStreamResource(s3Object), contentType);
+
+        } catch (NoSuchKeyException e) {
+            throw new StorageFileNotFoundException("File not found in storage: " + s3Key);
+        } catch (S3Exception e) {
+            throw new RuntimeException("Storage Error: " + e.getMessage());
         }
-
-        return new S3FileDownload(new InputStreamResource(s3Object), contentType);
-
-    } catch (NoSuchKeyException e) {
-        throw new StorageFileNotFoundException("File not found in storage: " + s3Key);
-    } catch (S3Exception e) {
-        throw new RuntimeException("Storage Error: " + e.getMessage());
     }
-}
-    // Helper Record to carry the stream and metadata back to the controller
+
+    /**
+     * Downloads a file from S3/MinIO and returns its raw bytes.
+     * Used for hash backfill — callers are responsible for not calling this on large files unnecessarily.
+     */
+    public byte[] downloadFileBytes(String s3Key) throws IOException {
+        try {
+            GetObjectRequest getObjectRequest = GetObjectRequest.builder()
+                    .bucket(bucketName)
+                    .key(s3Key)
+                    .build();
+            try (InputStream in = s3Client.getObject(getObjectRequest)) {
+                return in.readAllBytes();
+            }
+        } catch (NoSuchKeyException e) {
+            throw new StorageFileNotFoundException("File not found in storage: " + s3Key);
+        } catch (S3Exception e) {
+            throw new IOException("Failed to download file from storage: " + e.getMessage(), e);
+        }
+    }
+
+    // ─── private helpers ──────────────────────────────────────────────────────
+
+    private static String sha256Hex(byte[] bytes) {
+        try {
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            byte[] hash = digest.digest(bytes);
+            StringBuilder sb = new StringBuilder(64);
+            for (byte b : hash) {
+                sb.append(String.format("%02x", b));
+            }
+            return sb.toString();
+        } catch (NoSuchAlgorithmException e) {
+            throw new IllegalStateException("SHA-256 not available", e);
+        }
+    }
+
+    // ─── result types ─────────────────────────────────────────────────────────
+
+    /** Carries the S3 object key and the content hash back to the caller. */
+    public record UploadResult(String s3Key, String fileHash) {}
+
+    /** Carries the download stream and content type. */
     public record S3FileDownload(InputStreamResource resource, String contentType) {}
 
-    // Custom Exception
     public static class StorageFileNotFoundException extends RuntimeException {
         public StorageFileNotFoundException(String message) { super(message); }
     }

backend/src/main/resources/db/migration/V13__add_file_hash.sql

@@ -0,0 +1,7 @@
+-- Add content-based file hash to documents for annotation versioning
+ALTER TABLE documents
+    ADD COLUMN file_hash VARCHAR(64);
+
+-- Each annotation remembers which file version it was created against
+ALTER TABLE document_annotations
+    ADD COLUMN file_hash VARCHAR(64);

backend/src/test/java/org/raddatz/familienarchiv/controller/AdminControllerTest.java

@@ -58,4 +58,29 @@ class AdminControllerTest {
                 .andExpect(status().isOk())
                 .andExpect(jsonPath("$.count").value(1));
     }
+
+    // ─── POST /api/admin/backfill-file-hashes ──────────────────────────────────
+
+    @Test
+    void backfillFileHashes_returns401_whenUnauthenticated() throws Exception {
+        mockMvc.perform(post("/api/admin/backfill-file-hashes"))
+                .andExpect(status().isUnauthorized());
+    }
+
+    @Test
+    @WithMockUser(roles = "USER")
+    void backfillFileHashes_returns403_whenNotAdmin() throws Exception {
+        mockMvc.perform(post("/api/admin/backfill-file-hashes"))
+                .andExpect(status().isForbidden());
+    }
+
+    @Test
+    @WithMockUser(authorities = "ADMIN")
+    void backfillFileHashes_returns200_withCount_whenAdmin() throws Exception {
+        when(documentService.backfillFileHashes()).thenReturn(3);
+
+        mockMvc.perform(post("/api/admin/backfill-file-hashes"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$.count").value(3));
+    }
 }

backend/src/test/java/org/raddatz/familienarchiv/controller/AnnotationControllerTest.java

@@ -4,10 +4,12 @@ import org.junit.jupiter.api.Test;
 import org.raddatz.familienarchiv.config.SecurityConfig;
 import org.raddatz.familienarchiv.exception.DomainException;
 import org.raddatz.familienarchiv.exception.ErrorCode;
+import org.raddatz.familienarchiv.model.Document;
 import org.raddatz.familienarchiv.model.DocumentAnnotation;
 import org.raddatz.familienarchiv.security.PermissionAspect;
 import org.raddatz.familienarchiv.service.AnnotationService;
 import org.raddatz.familienarchiv.service.CustomUserDetailsService;
+import org.raddatz.familienarchiv.service.DocumentService;
 import org.raddatz.familienarchiv.service.UserService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.aop.AopAutoConfiguration;
@@ -36,6 +38,7 @@ class AnnotationControllerTest {
     @Autowired MockMvc mockMvc;
 
     @MockitoBean AnnotationService annotationService;
+    @MockitoBean DocumentService documentService;
     @MockitoBean UserService userService;
     @MockitoBean CustomUserDetailsService customUserDetailsService;
 
@@ -85,7 +88,8 @@ class AnnotationControllerTest {
         DocumentAnnotation saved = DocumentAnnotation.builder()
                 .id(UUID.randomUUID()).documentId(docId).pageNumber(1)
                 .x(0.1).y(0.1).width(0.2).height(0.2).color("#ff0000").build();
-        when(annotationService.createAnnotation(any(), any(), any())).thenReturn(saved);
+        when(documentService.getDocumentById(any())).thenReturn(Document.builder().build());
+        when(annotationService.createAnnotation(any(), any(), any(), any())).thenReturn(saved);
 
         mockMvc.perform(post("/api/documents/" + docId + "/annotations")
                         .contentType(MediaType.APPLICATION_JSON)
@@ -97,7 +101,8 @@ class AnnotationControllerTest {
     @Test
     @WithMockUser(authorities = "ANNOTATE_ALL")
     void createAnnotation_returns409_whenOverlap() throws Exception {
-        when(annotationService.createAnnotation(any(), any(), any()))
+        when(documentService.getDocumentById(any())).thenReturn(Document.builder().build());
+        when(annotationService.createAnnotation(any(), any(), any(), any()))
                 .thenThrow(DomainException.conflict(ErrorCode.ANNOTATION_OVERLAP, "Overlap"));
 
         mockMvc.perform(post("/api/documents/" + UUID.randomUUID() + "/annotations")

backend/src/test/java/org/raddatz/familienarchiv/service/AnnotationServiceTest.java

@@ -44,7 +44,7 @@ class AnnotationServiceTest {
         when(annotationRepository.findByDocumentIdAndPageNumber(docId, 1))
                 .thenReturn(List.of(existing));
 
-        assertThatThrownBy(() -> annotationService.createAnnotation(docId, dto, userId))
+        assertThatThrownBy(() -> annotationService.createAnnotation(docId, dto, userId, null))
                 .isInstanceOf(DomainException.class)
                 .satisfies(e -> assertThat(((DomainException) e).getStatus()).isEqualTo(CONFLICT));
 
@@ -63,7 +63,7 @@ class AnnotationServiceTest {
                 .x(0.0).y(0.0).width(0.05).height(0.05).color("#ff0000").createdBy(userId).build();
         when(annotationRepository.save(any())).thenReturn(saved);
 
-        DocumentAnnotation result = annotationService.createAnnotation(docId, dto, userId);
+        DocumentAnnotation result = annotationService.createAnnotation(docId, dto, userId, null);
 
         assertThat(result).isEqualTo(saved);
         verify(annotationRepository).save(any());
@@ -117,6 +117,35 @@ class AnnotationServiceTest {
         verify(annotationRepository).delete(annotation);
     }
 
+    @Test
+    void createAnnotation_setsFileHash_whenProvided() {
+        UUID docId = UUID.randomUUID();
+        UUID userId = UUID.randomUUID();
+        CreateAnnotationDTO dto = new CreateAnnotationDTO(1, 0.0, 0.0, 0.05, 0.05, "#ff0000");
+        String fileHash = "abc123";
+
+        when(annotationRepository.findByDocumentIdAndPageNumber(docId, 1)).thenReturn(List.of());
+        when(annotationRepository.save(any())).thenAnswer(inv -> inv.getArgument(0));
+
+        DocumentAnnotation result = annotationService.createAnnotation(docId, dto, userId, fileHash);
+
+        assertThat(result.getFileHash()).isEqualTo(fileHash);
+    }
+
+    @Test
+    void createAnnotation_setsNullFileHash_whenNoneProvided() {
+        UUID docId = UUID.randomUUID();
+        UUID userId = UUID.randomUUID();
+        CreateAnnotationDTO dto = new CreateAnnotationDTO(1, 0.0, 0.0, 0.05, 0.05, "#ff0000");
+
+        when(annotationRepository.findByDocumentIdAndPageNumber(docId, 1)).thenReturn(List.of());
+        when(annotationRepository.save(any())).thenAnswer(inv -> inv.getArgument(0));
+
+        DocumentAnnotation result = annotationService.createAnnotation(docId, dto, userId, null);
+
+        assertThat(result.getFileHash()).isNull();
+    }
+
     // ─── listAnnotations ──────────────────────────────────────────────────────
 
     @Test
@@ -128,4 +157,30 @@ class AnnotationServiceTest {
 
         assertThat(annotationService.listAnnotations(docId)).containsExactly(a);
     }
+
+    // ─── backfillAnnotationFileHashForDocument ────────────────────────────────
+
+    @Test
+    void backfillAnnotationFileHashForDocument_setsHashOnAnnotationsWithNullHash() {
+        UUID docId = UUID.randomUUID();
+        String hash = "abc123";
+        DocumentAnnotation a = DocumentAnnotation.builder()
+                .id(UUID.randomUUID()).documentId(docId).build();
+        when(annotationRepository.findByDocumentIdAndFileHashIsNull(docId)).thenReturn(List.of(a));
+
+        annotationService.backfillAnnotationFileHashForDocument(docId, hash);
+
+        assertThat(a.getFileHash()).isEqualTo(hash);
+        verify(annotationRepository).save(a);
+    }
+
+    @Test
+    void backfillAnnotationFileHashForDocument_doesNothingWhenNoAnnotations() {
+        UUID docId = UUID.randomUUID();
+        when(annotationRepository.findByDocumentIdAndFileHashIsNull(docId)).thenReturn(List.of());
+
+        annotationService.backfillAnnotationFileHashForDocument(docId, "hash");
+
+        verify(annotationRepository, never()).save(any());
+    }
 }

backend/src/test/java/org/raddatz/familienarchiv/service/DocumentServiceTest.java

@@ -21,6 +21,7 @@ import java.util.UUID;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.*;
 
 @ExtendWith(MockitoExtension.class)
@@ -31,6 +32,7 @@ class DocumentServiceTest {
     @Mock FileService fileService;
     @Mock TagService tagService;
     @Mock DocumentVersionService documentVersionService;
+    @Mock AnnotationService annotationService;
     @InjectMocks DocumentService documentService;
 
     // ─── getDocumentById ──────────────────────────────────────────────────────
@@ -135,6 +137,48 @@ class DocumentServiceTest {
         assertThat(documentService.getDocumentsByReceiver(receiverId)).containsExactly(doc);
     }
 
+    // ─── file hash propagation ───────────────────────────────────────────────
+
+    @Test
+    void createDocument_setsFileHashFromUpload_whenFileProvided() throws Exception {
+        DocumentUpdateDTO dto = new DocumentUpdateDTO();
+        dto.setTitle("Doc");
+        org.springframework.mock.web.MockMultipartFile file =
+                new org.springframework.mock.web.MockMultipartFile("file", "scan.pdf", "application/pdf", new byte[]{1});
+        FileService.UploadResult uploadResult = new FileService.UploadResult("documents/uuid_scan.pdf", "deadbeef");
+
+        Document savedDoc = Document.builder().id(UUID.randomUUID()).title("Doc")
+                .originalFilename("scan.pdf").status(DocumentStatus.PLACEHOLDER).build();
+        when(documentRepository.save(any())).thenReturn(savedDoc);
+        when(documentRepository.findById(any())).thenReturn(Optional.of(savedDoc));
+        when(fileService.uploadFile(any(), any())).thenReturn(uploadResult);
+
+        documentService.createDocument(dto, file);
+
+        org.mockito.ArgumentCaptor<Document> captor = org.mockito.ArgumentCaptor.forClass(Document.class);
+        verify(documentRepository, atLeastOnce()).save(captor.capture());
+        assertThat(captor.getAllValues()).anySatisfy(d -> assertThat(d.getFileHash()).isEqualTo("deadbeef"));
+    }
+
+    @Test
+    void updateDocument_setsFileHashFromUpload_whenNewFileProvided() throws Exception {
+        UUID id = UUID.randomUUID();
+        Document existing = Document.builder()
+                .id(id).title("Alt").originalFilename("old.pdf")
+                .status(DocumentStatus.UPLOADED).build();
+        org.springframework.mock.web.MockMultipartFile newFile =
+                new org.springframework.mock.web.MockMultipartFile("file", "new.pdf", "application/pdf", new byte[]{2});
+        FileService.UploadResult uploadResult = new FileService.UploadResult("documents/uuid_new.pdf", "cafebabe");
+
+        when(documentRepository.findById(id)).thenReturn(Optional.of(existing));
+        when(fileService.uploadFile(any(), any())).thenReturn(uploadResult);
+        when(documentRepository.save(any())).thenReturn(existing);
+
+        documentService.updateDocument(id, new DocumentUpdateDTO(), newFile);
+
+        assertThat(existing.getFileHash()).isEqualTo("cafebabe");
+    }
+
     // ─── versioning ───────────────────────────────────────────────────────────
 
     @Test
@@ -167,4 +211,59 @@ class DocumentServiceTest {
 
         verify(documentVersionService).recordVersion(any(Document.class));
     }
+
+    // ─── backfillFileHashes ───────────────────────────────────────────────────
+
+    @Test
+    void backfillFileHashes_skipsDocumentsWithNoFilePath() throws Exception {
+        Document noFile = Document.builder().id(UUID.randomUUID()).build();
+        when(documentRepository.findByFileHashIsNullAndFilePathIsNotNull()).thenReturn(List.of());
+
+        int count = documentService.backfillFileHashes();
+
+        assertThat(count).isZero();
+        verify(fileService, never()).downloadFileBytes(any());
+    }
+
+    @Test
+    void backfillFileHashes_computesHashAndSavesDocument() throws Exception {
+        UUID docId = UUID.randomUUID();
+        Document doc = Document.builder().id(docId).filePath("documents/scan.pdf").build();
+        when(documentRepository.findByFileHashIsNullAndFilePathIsNotNull()).thenReturn(List.of(doc));
+        when(fileService.downloadFileBytes("documents/scan.pdf")).thenReturn(new byte[]{1, 2, 3});
+        when(documentRepository.save(any())).thenAnswer(inv -> inv.getArgument(0));
+
+        documentService.backfillFileHashes();
+
+        assertThat(doc.getFileHash()).isNotNull().hasSize(64);
+        verify(documentRepository).save(doc);
+    }
+
+    @Test
+    void backfillFileHashes_propagatesHashToAnnotations() throws Exception {
+        UUID docId = UUID.randomUUID();
+        Document doc = Document.builder().id(docId).filePath("documents/scan.pdf").build();
+        when(documentRepository.findByFileHashIsNullAndFilePathIsNotNull()).thenReturn(List.of(doc));
+        when(fileService.downloadFileBytes("documents/scan.pdf")).thenReturn(new byte[]{1, 2, 3});
+        when(documentRepository.save(any())).thenAnswer(inv -> inv.getArgument(0));
+
+        documentService.backfillFileHashes();
+
+        verify(annotationService).backfillAnnotationFileHashForDocument(eq(docId), any());
+    }
+
+    @Test
+    void backfillFileHashes_returnsCountOfUpdatedDocuments() throws Exception {
+        UUID id1 = UUID.randomUUID();
+        UUID id2 = UUID.randomUUID();
+        Document doc1 = Document.builder().id(id1).filePath("documents/a.pdf").build();
+        Document doc2 = Document.builder().id(id2).filePath("documents/b.pdf").build();
+        when(documentRepository.findByFileHashIsNullAndFilePathIsNotNull()).thenReturn(List.of(doc1, doc2));
+        when(fileService.downloadFileBytes(any())).thenReturn(new byte[]{1});
+        when(documentRepository.save(any())).thenAnswer(inv -> inv.getArgument(0));
+
+        int count = documentService.backfillFileHashes();
+
+        assertThat(count).isEqualTo(2);
+    }
 }

backend/src/test/java/org/raddatz/familienarchiv/service/FileServiceTest.java

@@ -0,0 +1,85 @@
+package org.raddatz.familienarchiv.service;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentCaptor;
+import org.springframework.mock.web.MockMultipartFile;
+import software.amazon.awssdk.core.sync.RequestBody;
+import software.amazon.awssdk.services.s3.S3Client;
+import software.amazon.awssdk.services.s3.model.PutObjectRequest;
+
+import java.io.IOException;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+class FileServiceTest {
+
+    private S3Client s3Client;
+    private FileService fileService;
+
+    @BeforeEach
+    void setUp() {
+        s3Client = mock(S3Client.class);
+        fileService = new FileService(s3Client, "test-bucket");
+    }
+
+    @Test
+    void uploadFile_returnsS3Key() throws IOException {
+        MockMultipartFile file = new MockMultipartFile(
+                "file", "test.pdf", "application/pdf", new byte[]{1, 2, 3});
+
+        FileService.UploadResult result = fileService.uploadFile(file, "test.pdf");
+
+        assertThat(result.s3Key()).startsWith("documents/");
+        assertThat(result.s3Key()).endsWith("_test.pdf");
+        verify(s3Client).putObject(any(PutObjectRequest.class), any(RequestBody.class));
+    }
+
+    @Test
+    void uploadFile_returnsCorrectSha256FileHash() throws IOException, NoSuchAlgorithmException {
+        byte[] content = "hello pdf content".getBytes();
+        MockMultipartFile file = new MockMultipartFile(
+                "file", "doc.pdf", "application/pdf", content);
+
+        FileService.UploadResult result = fileService.uploadFile(file, "doc.pdf");
+
+        // Compute expected hash independently
+        MessageDigest digest = MessageDigest.getInstance("SHA-256");
+        byte[] hashBytes = digest.digest(content);
+        StringBuilder expected = new StringBuilder();
+        for (byte b : hashBytes) {
+            expected.append(String.format("%02x", b));
+        }
+
+        assertThat(result.fileHash()).isEqualTo(expected.toString());
+    }
+
+    @Test
+    void uploadFile_differentContents_produceDifferentHashes() throws IOException {
+        MockMultipartFile file1 = new MockMultipartFile(
+                "f", "a.pdf", "application/pdf", new byte[]{1, 2, 3});
+        MockMultipartFile file2 = new MockMultipartFile(
+                "f", "b.pdf", "application/pdf", new byte[]{4, 5, 6});
+
+        FileService.UploadResult r1 = fileService.uploadFile(file1, "a.pdf");
+        FileService.UploadResult r2 = fileService.uploadFile(file2, "b.pdf");
+
+        assertThat(r1.fileHash()).isNotEqualTo(r2.fileHash());
+    }
+
+    @Test
+    void uploadFile_sameContents_produceSameHash() throws IOException {
+        byte[] content = new byte[]{10, 20, 30};
+        MockMultipartFile file1 = new MockMultipartFile("f", "x.pdf", "application/pdf", content);
+        MockMultipartFile file2 = new MockMultipartFile("f", "y.pdf", "application/pdf", content);
+
+        FileService.UploadResult r1 = fileService.uploadFile(file1, "x.pdf");
+        FileService.UploadResult r2 = fileService.uploadFile(file2, "y.pdf");
+
+        assertThat(r1.fileHash()).isEqualTo(r2.fileHash());
+    }
+}

frontend/e2e/admin.spec.ts

@@ -216,3 +216,35 @@ test.describe('Admin — tag management', () => {
 		await page.screenshot({ path: 'test-results/e2e/admin-tag-restored.png' });
 	});
 });
+
+// ─── System tab — backfill file hashes ────────────────────────────────────────
+
+test.describe('Admin system tab — backfill file hashes', () => {
+	test('admin triggers file hash backfill and sees success message', async ({ request, page }) => {
+		test.setTimeout(60_000);
+
+		// Create a document via API so there is at least one without a hash
+		const createRes = await request.post('/api/documents', {
+			multipart: { title: 'E2E Backfill Hash Test' }
+		});
+		if (!createRes.ok()) throw new Error(`Create failed: ${createRes.status()}`);
+
+		await page.goto('/admin');
+		await page.waitForSelector('[data-hydrated]');
+
+		// Navigate to System tab
+		await page.getByRole('button', { name: /system/i }).click();
+
+		// Click the backfill hashes button
+		const btn = page.getByRole('button', { name: /datei-hashes berechnen/i });
+		await expect(btn).toBeVisible();
+		await btn.click();
+
+		// Success message must appear (count >= 0)
+		await expect(page.locator('text=/\\d+ Dokumente wurden aktualisiert/i')).toBeVisible({
+			timeout: 15000
+		});
+
+		await page.screenshot({ path: 'test-results/e2e/admin-backfill-hashes.png' });
+	});
+});

frontend/e2e/bottom-panel.spec.ts

@@ -1,180 +0,0 @@
-import { test, expect } from '@playwright/test';
-import path from 'path';
-import { fileURLToPath } from 'url';
-import fs from 'fs';
-
-const __dirname = path.dirname(fileURLToPath(import.meta.url));
-const PDF_FIXTURE = path.resolve(__dirname, 'fixtures/minimal.pdf');
-
-/**
- * Bottom panel E2E tests — issue #62.
- * Verifies the new document detail layout: full-viewport viewer + floating bottom panel.
- */
-
-let pdfDocHref: string;
-let noFileDocHref: string;
-
-test.describe('Document bottom panel', () => {
-	test.beforeAll(async ({ request }) => {
-		const baseURL = process.env.E2E_BASE_URL ?? 'http://localhost:3000';
-
-		// Create a document with a PDF and a date for metadata tests.
-		const createRes = await request.post('/api/documents', {
-			multipart: { title: 'E2E Bottom Panel Test', documentDate: '1945-05-08' }
-		});
-		if (!createRes.ok()) throw new Error(`Create document failed: ${createRes.status()}`);
-		const doc = await createRes.json();
-
-		const uploadRes = await request.put(`/api/documents/${doc.id}`, {
-			multipart: {
-				title: doc.title,
-				documentDate: '1945-05-08',
-				transcription: 'Dies ist eine vollständige Transkription des Dokuments für den E2E-Test.',
-				file: {
-					name: 'minimal.pdf',
-					mimeType: 'application/pdf',
-					buffer: fs.readFileSync(PDF_FIXTURE)
-				}
-			}
-		});
-		if (!uploadRes.ok()) throw new Error(`Upload PDF failed: ${uploadRes.status()}`);
-		pdfDocHref = `${baseURL}/documents/${doc.id}`;
-
-		// Create a document WITHOUT a file — panel should open to Metadaten by default.
-		const noFileRes = await request.post('/api/documents', {
-			multipart: { title: 'E2E Bottom Panel No-File Test' }
-		});
-		if (!noFileRes.ok()) throw new Error(`Create no-file document failed: ${noFileRes.status()}`);
-		noFileDocHref = `${baseURL}/documents/${noFileRes.json().then ? (await noFileRes.json()).id : ''}`;
-		const noFileDoc = await noFileRes.json();
-		noFileDocHref = `${baseURL}/documents/${noFileDoc.id}`;
-	});
-
-	test('bottom panel tab bar is visible and panel content is closed by default on a PDF document', async ({
-		page
-	}) => {
-		test.setTimeout(30_000);
-		// Clear localStorage to ensure no previous panel state.
-		await page.goto(pdfDocHref);
-		await page.evaluate(() => localStorage.clear());
-		await page.reload();
-		await page.waitForSelector('[data-hydrated]');
-
-		// Tab bar must always be visible.
-		await expect(page.getByRole('button', { name: 'Metadaten' })).toBeVisible();
-		await expect(page.getByRole('button', { name: 'Transkription' })).toBeVisible();
-		await expect(page.getByRole('button', { name: 'Diskussion' })).toBeVisible();
-		await expect(page.getByRole('button', { name: 'Verlauf' })).toBeVisible();
-
-		// Panel content must NOT be visible when closed.
-		await expect(page.locator('[data-testid="bottom-panel-content"]')).not.toBeVisible();
-
-		await page.screenshot({ path: 'test-results/e2e/bottom-panel-closed-default.png' });
-	});
-
-	test('clicking Metadaten tab opens the panel and shows metadata content', async ({ page }) => {
-		test.setTimeout(30_000);
-		await page.goto(pdfDocHref);
-		await page.evaluate(() => localStorage.clear());
-		await page.reload();
-		await page.waitForSelector('[data-hydrated]');
-
-		await page.getByRole('button', { name: 'Metadaten' }).click();
-
-		// Panel content becomes visible.
-		await expect(page.locator('[data-testid="bottom-panel-content"]')).toBeVisible();
-
-		// Metadata section heading should be present.
-		await expect(page.getByText('Details', { exact: false })).toBeVisible();
-
-		await page.screenshot({ path: 'test-results/e2e/bottom-panel-metadata.png' });
-	});
-
-	test('clicking Transkription tab shows transcription text', async ({ page }) => {
-		test.setTimeout(30_000);
-		await page.goto(pdfDocHref);
-		await page.evaluate(() => localStorage.clear());
-		await page.reload();
-		await page.waitForSelector('[data-hydrated]');
-
-		await page.getByRole('button', { name: 'Transkription' }).click();
-
-		await expect(page.locator('[data-testid="bottom-panel-content"]')).toBeVisible();
-		await expect(
-			page.getByText('Dies ist eine vollständige Transkription', { exact: false })
-		).toBeVisible();
-
-		await page.screenshot({ path: 'test-results/e2e/bottom-panel-transcription.png' });
-	});
-
-	test('clicking Diskussion tab shows the comment input', async ({ page }) => {
-		test.setTimeout(30_000);
-		await page.goto(pdfDocHref);
-		await page.evaluate(() => localStorage.clear());
-		await page.reload();
-		await page.waitForSelector('[data-hydrated]');
-
-		await page.getByRole('button', { name: 'Diskussion' }).click();
-
-		await expect(page.locator('[data-testid="bottom-panel-content"]')).toBeVisible();
-		await expect(page.getByPlaceholder('Kommentar schreiben…')).toBeVisible();
-
-		await page.screenshot({ path: 'test-results/e2e/bottom-panel-discussion.png' });
-	});
-
-	test('clicking × close button collapses the panel content', async ({ page }) => {
-		test.setTimeout(30_000);
-		await page.goto(pdfDocHref);
-		await page.evaluate(() => localStorage.clear());
-		await page.reload();
-		await page.waitForSelector('[data-hydrated]');
-
-		// Open the panel first.
-		await page.getByRole('button', { name: 'Metadaten' }).click();
-		await expect(page.locator('[data-testid="bottom-panel-content"]')).toBeVisible();
-
-		// Close it.
-		await page.locator('[data-testid="panel-close-btn"]').click();
-		await expect(page.locator('[data-testid="bottom-panel-content"]')).not.toBeVisible();
-
-		// Tab bar still visible after closing.
-		await expect(page.getByRole('button', { name: 'Metadaten' })).toBeVisible();
-
-		await page.screenshot({ path: 'test-results/e2e/bottom-panel-closed-after-x.png' });
-	});
-
-	test('panel open state persists after page reload', async ({ page }) => {
-		test.setTimeout(30_000);
-		await page.goto(pdfDocHref);
-		await page.evaluate(() => localStorage.clear());
-		await page.reload();
-		await page.waitForSelector('[data-hydrated]');
-
-		// Open the panel to Diskussion.
-		await page.getByRole('button', { name: 'Diskussion' }).click();
-		await expect(page.locator('[data-testid="bottom-panel-content"]')).toBeVisible();
-
-		// Reload — panel should re-open on the same tab.
-		await page.reload();
-		await page.waitForSelector('[data-hydrated]');
-
-		await expect(page.locator('[data-testid="bottom-panel-content"]')).toBeVisible();
-		await expect(page.getByPlaceholder('Kommentar schreiben…')).toBeVisible();
-
-		await page.screenshot({ path: 'test-results/e2e/bottom-panel-persisted.png' });
-	});
-
-	test('document without a file opens panel to Metadaten by default', async ({ page }) => {
-		test.setTimeout(30_000);
-		await page.goto(noFileDocHref);
-		await page.evaluate(() => localStorage.clear());
-		await page.reload();
-		await page.waitForSelector('[data-hydrated]');
-
-		// Panel should be open to Metadaten by default when there is no file.
-		await expect(page.locator('[data-testid="bottom-panel-content"]')).toBeVisible();
-		await expect(page.getByText('Details', { exact: false })).toBeVisible();
-
-		await page.screenshot({ path: 'test-results/e2e/bottom-panel-no-file-default.png' });
-	});
-});

frontend/e2e/documents.spec.ts

@@ -347,13 +347,142 @@ test.describe('PDF annotations — admin', () => {
 	});
 });
 
+// ─── PDF Annotations — file hash (version awareness) ─────────────────────────
+
+test.describe('PDF annotations — file hash versioning', () => {
+	const baseURL = process.env.E2E_BASE_URL ?? 'http://localhost:3000';
+	const PDF_FIXTURE2 = path.resolve(__dirname, 'fixtures/minimal2.pdf');
+
+	test('annotations are hidden after a different file is uploaded', async ({ page, request }) => {
+		test.setTimeout(90_000);
+
+		// 1. Create document and upload original PDF
+		const createRes = await request.post('/api/documents', {
+			multipart: { title: 'E2E Hash Test — version' }
+		});
+		if (!createRes.ok()) throw new Error(`Create failed: ${createRes.status()}`);
+		const doc = await createRes.json();
+
+		const uploadRes = await request.put(`/api/documents/${doc.id}`, {
+			multipart: {
+				title: doc.title,
+				file: {
+					name: 'minimal.pdf',
+					mimeType: 'application/pdf',
+					buffer: fs.readFileSync(PDF_FIXTURE)
+				}
+			}
+		});
+		if (!uploadRes.ok()) throw new Error(`Upload failed: ${uploadRes.status()}`);
+
+		// 2. Create an annotation via API
+		const annotRes = await request.post(`/api/documents/${doc.id}/annotations`, {
+			data: { pageNumber: 1, x: 0.1, y: 0.1, width: 0.2, height: 0.2, color: '#ff0000' }
+		});
+		if (!annotRes.ok()) throw new Error(`Create annotation failed: ${annotRes.status()}`);
+
+		// 3. Verify annotation appears before re-upload
+		await page.goto(`${baseURL}/documents/${doc.id}`);
+		await page.waitForSelector('[data-hydrated]');
+		await page.locator('canvas').first().waitFor({ state: 'visible', timeout: 20000 });
+		await expect(page.locator('[data-testid^="annotation-"]').first()).toBeVisible({
+			timeout: 8000
+		});
+
+		// 4. Upload a different file (different hash)
+		const reuploadRes = await request.put(`/api/documents/${doc.id}`, {
+			multipart: {
+				title: doc.title,
+				file: {
+					name: 'minimal2.pdf',
+					mimeType: 'application/pdf',
+					buffer: fs.readFileSync(PDF_FIXTURE2)
+				}
+			}
+		});
+		if (!reuploadRes.ok()) throw new Error(`Re-upload failed: ${reuploadRes.status()}`);
+
+		// 5. Reload — annotation must be hidden and notice shown
+		await page.reload();
+		await page.waitForSelector('[data-hydrated]');
+		await page.locator('canvas').first().waitFor({ state: 'visible', timeout: 20000 });
+
+		await expect(page.locator('[data-testid^="annotation-"]')).toHaveCount(0, { timeout: 8000 });
+		await expect(page.locator('[data-testid="annotation-outdated-notice"]')).toBeVisible({
+			timeout: 5000
+		});
+
+		await page.screenshot({ path: 'test-results/e2e/annotation-hidden-after-reupload.png' });
+	});
+
+	test('annotations reappear after re-uploading the original file', async ({ page, request }) => {
+		test.setTimeout(90_000);
+
+		// 1. Create document and upload original PDF
+		const createRes = await request.post('/api/documents', {
+			multipart: { title: 'E2E Hash Test — restore' }
+		});
+		if (!createRes.ok()) throw new Error(`Create failed: ${createRes.status()}`);
+		const doc = await createRes.json();
+
+		const originalBytes = fs.readFileSync(PDF_FIXTURE);
+		const uploadRes = await request.put(`/api/documents/${doc.id}`, {
+			multipart: {
+				title: doc.title,
+				file: { name: 'minimal.pdf', mimeType: 'application/pdf', buffer: originalBytes }
+			}
+		});
+		if (!uploadRes.ok()) throw new Error(`Upload failed: ${uploadRes.status()}`);
+
+		// 2. Create annotation
+		const annotRes = await request.post(`/api/documents/${doc.id}/annotations`, {
+			data: { pageNumber: 1, x: 0.1, y: 0.1, width: 0.2, height: 0.2, color: '#0000ff' }
+		});
+		if (!annotRes.ok()) throw new Error(`Create annotation failed: ${annotRes.status()}`);
+
+		// 3. Replace with different file
+		const replaceRes = await request.put(`/api/documents/${doc.id}`, {
+			multipart: {
+				title: doc.title,
+				file: {
+					name: 'minimal2.pdf',
+					mimeType: 'application/pdf',
+					buffer: fs.readFileSync(PDF_FIXTURE2)
+				}
+			}
+		});
+		if (!replaceRes.ok()) throw new Error(`Replace failed: ${replaceRes.status()}`);
+
+		// 4. Re-upload original file (restoring the hash)
+		const restoreRes = await request.put(`/api/documents/${doc.id}`, {
+			multipart: {
+				title: doc.title,
+				file: { name: 'minimal.pdf', mimeType: 'application/pdf', buffer: originalBytes }
+			}
+		});
+		if (!restoreRes.ok()) throw new Error(`Restore failed: ${restoreRes.status()}`);
+
+		// 5. Verify annotation reappears and notice is gone
+		await page.goto(`${baseURL}/documents/${doc.id}`);
+		await page.waitForSelector('[data-hydrated]');
+		await page.locator('canvas').first().waitFor({ state: 'visible', timeout: 20000 });
+
+		await expect(page.locator('[data-testid^="annotation-"]').first()).toBeVisible({
+			timeout: 8000
+		});
+		await expect(page.locator('[data-testid="annotation-outdated-notice"]')).not.toBeVisible();
+
+		await page.screenshot({ path: 'test-results/e2e/annotation-restored.png' });
+	});
+});
+
 // ─── PDF Annotations (read-only user) ─────────────────────────────────────────
 
 test.describe('PDF annotations — read-only user', () => {
 	// Isolated session — does not share the admin storage state
 	test.use({ storageState: { cookies: [], origins: [] } });
 
-	test('read-only user sees a disabled Annotieren button', async ({ page }) => {
+	test('read-only user does not see the Annotieren button', async ({ page }) => {
 		test.setTimeout(60_000);
 		await page.goto('/login');
 		await page.getByLabel('Benutzername').fill('reader');
@@ -365,12 +494,10 @@ test.describe('PDF annotations — read-only user', () => {
 		const baseURL = process.env.E2E_BASE_URL ?? 'http://localhost:3000';
 		await page.goto(`${baseURL}/documents/${sharedAnnotationDocId}`);
 		await page.waitForSelector('[data-hydrated]');
-		// Wait for the PDF canvas — once rendered, the controls bar (with disabled button) is shown.
-		await page.locator('canvas').first().waitFor({ state: 'visible', timeout: 30000 });
 
-		const disabledBtn = page.getByRole('button', { name: /annotieren/i });
-		await expect(disabledBtn).toBeVisible({ timeout: 5000 });
-		await expect(disabledBtn).toBeDisabled();
+		// Reader users do not have ANNOTATE_ALL permission — the button must not be shown at all.
+		const annotateBtn = page.getByRole('button', { name: /annotieren/i });
+		await expect(annotateBtn).not.toBeVisible({ timeout: 5000 });
 
 		await page.screenshot({ path: 'test-results/e2e/annotations-button-reader.png' });
 	});

frontend/e2e/fixtures/minimal2.pdf

@@ -0,0 +1,21 @@
+%PDF-1.4
+1 0 obj
+<</Type/Catalog/Pages 2 0 R>>
+endobj
+2 0 obj
+<</Type/Pages/Kids[3 0 R]/Count 1>>
+endobj
+3 0 obj
+<</Type/Page/MediaBox[0 0 3 3]/Parent 2 0 R>>
+endobj
+xref
+0 4
+0000000000 65535 f 
+0000000009 00000 n 
+0000000058 00000 n 
+0000000115 00000 n 
+trailer
+<</Size 4/Root 1 0 R>>
+startxref
+190
+%%EOF

frontend/messages/de.json

@@ -2,6 +2,7 @@
 	"$schema": "https://inlang.com/schema/inlang-message-format",
 	"error_annotation_not_found": "Die Annotation wurde nicht gefunden.",
 	"error_annotation_overlap": "Die Annotation überschneidet sich mit einer vorhandenen.",
+	"annotation_outdated_notice": "Einige Annotationen beziehen sich auf eine frühere Dateiversion und werden nicht angezeigt.",
 	"error_document_not_found": "Das Dokument wurde nicht gefunden.",
 	"error_document_no_file": "Diesem Dokument ist noch keine Datei zugeordnet.",
 	"error_file_not_found": "Die Datei konnte im Speicher nicht gefunden werden.",
@@ -241,6 +242,10 @@
 	"admin_system_backfill_description": "Erstellt einen initialen Verlaufseintrag für alle Dokumente, die noch keinen Verlauf haben (z.B. importierte Dokumente). Dadurch werden beim nächsten Bearbeiten nur die tatsächlich geänderten Felder hervorgehoben.",
 	"admin_system_backfill_btn": "Jetzt auffüllen",
 	"admin_system_backfill_success": "{count} Dokumente wurden aufgefüllt.",
+	"admin_system_backfill_hashes_heading": "Datei-Hashes berechnen",
+	"admin_system_backfill_hashes_description": "Berechnet den SHA-256-Hash für alle bereits hochgeladenen Dokumente, die noch keinen Hash haben. Dadurch werden Annotationen korrekt mit ihrer Dateiversion verknüpft und wieder angezeigt.",
+	"admin_system_backfill_hashes_btn": "Datei-Hashes berechnen",
+	"admin_system_backfill_hashes_success": "{count} Dokumente wurden aktualisiert.",
 	"comp_expandable_show_more": "Mehr anzeigen",
 	"comp_expandable_show_less": "Weniger anzeigen",
 	"error_comment_not_found": "Der Kommentar wurde nicht gefunden.",
@@ -250,12 +255,5 @@
 	"comment_btn_reply": "Antworten",
 	"comment_edited_label": "· bearbeitet",
 	"comment_panel_title": "Kommentare",
-	"comment_panel_close": "Schließen",
-	"doc_panel_tab_metadata": "Metadaten",
-	"doc_panel_tab_transcription": "Transkription",
-	"doc_panel_tab_discussion": "Diskussion",
-	"doc_panel_tab_history": "Verlauf",
-	"doc_panel_annotate": "Annotieren",
-	"doc_panel_annotate_stop": "Fertig",
-	"doc_panel_annotation_thread_title": "Annotation"
+	"comment_panel_close": "Schließen"
 }

frontend/messages/en.json

@@ -2,6 +2,7 @@
 	"$schema": "https://inlang.com/schema/inlang-message-format",
 	"error_annotation_not_found": "Annotation not found.",
 	"error_annotation_overlap": "The annotation overlaps an existing one.",
+	"annotation_outdated_notice": "Some annotations refer to an earlier file version and are not shown.",
 	"error_document_not_found": "Document not found.",
 	"error_document_no_file": "No file is associated with this document.",
 	"error_file_not_found": "The file could not be found in storage.",
@@ -241,6 +242,10 @@
 	"admin_system_backfill_description": "Creates an initial history entry for all documents that do not have one yet (e.g. imported documents). This ensures that future edits only highlight actually changed fields.",
 	"admin_system_backfill_btn": "Backfill now",
 	"admin_system_backfill_success": "{count} documents were backfilled.",
+	"admin_system_backfill_hashes_heading": "Compute file hashes",
+	"admin_system_backfill_hashes_description": "Computes the SHA-256 hash for all previously uploaded documents that do not have one yet. This ensures annotations are correctly linked to their file version and shown again.",
+	"admin_system_backfill_hashes_btn": "Compute file hashes",
+	"admin_system_backfill_hashes_success": "{count} documents were updated.",
 	"comp_expandable_show_more": "Show more",
 	"comp_expandable_show_less": "Show less",
 	"error_comment_not_found": "The comment could not be found.",
@@ -250,12 +255,5 @@
 	"comment_btn_reply": "Reply",
 	"comment_edited_label": "· edited",
 	"comment_panel_title": "Comments",
-	"comment_panel_close": "Close",
-	"doc_panel_tab_metadata": "Metadata",
-	"doc_panel_tab_transcription": "Transcription",
-	"doc_panel_tab_discussion": "Discussion",
-	"doc_panel_tab_history": "History",
-	"doc_panel_annotate": "Annotate",
-	"doc_panel_annotate_stop": "Done",
-	"doc_panel_annotation_thread_title": "Annotation"
+	"comment_panel_close": "Close"
 }

frontend/messages/es.json

@@ -2,6 +2,7 @@
 	"$schema": "https://inlang.com/schema/inlang-message-format",
 	"error_annotation_not_found": "Anotación no encontrada.",
 	"error_annotation_overlap": "La anotación se superpone con una existente.",
+	"annotation_outdated_notice": "Algunas anotaciones hacen referencia a una versión anterior del archivo y no se muestran.",
 	"error_document_not_found": "Documento no encontrado.",
 	"error_document_no_file": "No hay ningún archivo asociado a este documento.",
 	"error_file_not_found": "El archivo no pudo encontrarse en el almacenamiento.",
@@ -241,6 +242,10 @@
 	"admin_system_backfill_description": "Crea una entrada de historial inicial para todos los documentos que aún no tienen ninguna (p.ej. documentos importados). Así, en la próxima edición solo se resaltarán los campos realmente modificados.",
 	"admin_system_backfill_btn": "Completar ahora",
 	"admin_system_backfill_success": "{count} documentos fueron completados.",
+	"admin_system_backfill_hashes_heading": "Calcular hashes de archivo",
+	"admin_system_backfill_hashes_description": "Calcula el hash SHA-256 para todos los documentos ya subidos que aún no tienen uno. Así las anotaciones se vinculan correctamente a su versión del archivo y vuelven a mostrarse.",
+	"admin_system_backfill_hashes_btn": "Calcular hashes de archivo",
+	"admin_system_backfill_hashes_success": "{count} documentos fueron actualizados.",
 	"comp_expandable_show_more": "Mostrar más",
 	"comp_expandable_show_less": "Mostrar menos",
 	"error_comment_not_found": "El comentario no pudo encontrarse.",
@@ -250,12 +255,5 @@
 	"comment_btn_reply": "Responder",
 	"comment_edited_label": "· editado",
 	"comment_panel_title": "Comentarios",
-	"comment_panel_close": "Cerrar",
-	"doc_panel_tab_metadata": "Metadatos",
-	"doc_panel_tab_transcription": "Transcripción",
-	"doc_panel_tab_discussion": "Discusión",
-	"doc_panel_tab_history": "Historial",
-	"doc_panel_annotate": "Anotar",
-	"doc_panel_annotate_stop": "Listo",
-	"doc_panel_annotation_thread_title": "Anotación"
+	"comment_panel_close": "Cerrar"
 }

frontend/src/lib/components/DocumentBottomPanel.svelte

@@ -1,196 +0,0 @@
-<script lang="ts">
-import { m } from '$lib/paraglide/messages.js';
-import PanelMetadata from './PanelMetadata.svelte';
-import PanelTranscription from './PanelTranscription.svelte';
-import PanelDiscussion from './PanelDiscussion.svelte';
-import PanelHistory from './PanelHistory.svelte';
-
-type Tab = 'metadata' | 'transcription' | 'discussion' | 'history';
-
-type CommentReply = {
-	id: string;
-	authorId: string | null;
-	authorName: string;
-	content: string;
-	createdAt: string;
-	updatedAt: string;
-};
-
-type Comment = {
-	id: string;
-	authorId: string | null;
-	authorName: string;
-	content: string;
-	createdAt: string;
-	updatedAt: string;
-	replies: CommentReply[];
-};
-
-type Doc = {
-	id: string;
-	title?: string | null;
-	documentDate?: string | null;
-	location?: string | null;
-	documentLocation?: string | null;
-	tags?: { id: string; name: string }[] | null;
-	sender?: { id: string; firstName: string; lastName: string; alias?: string | null } | null;
-	receivers?: { id: string; firstName: string; lastName: string }[] | null;
-	summary?: string | null;
-	transcription?: string | null;
-};
-
-type Props = {
-	doc: Doc;
-	comments: Comment[];
-	canComment: boolean;
-	currentUserId: string | null;
-	canAdmin: boolean;
-	open: boolean;
-	height: number;
-	activeTab: Tab;
-	activeAnnotationId: string | null;
-	onAnnotationCommentCountChange?: (annotationId: string, count: number) => void;
-};
-
-let {
-	doc,
-	comments,
-	canComment,
-	currentUserId,
-	canAdmin,
-	open = $bindable(),
-	height = $bindable(),
-	activeTab = $bindable(),
-	activeAnnotationId,
-	onAnnotationCommentCountChange
-}: Props = $props();
-
-const MIN_HEIGHT = 52; // drag handle (8px) + tab bar (~44px)
-const DEFAULT_HEIGHT = 320;
-
-let isDragging = $state(false);
-let dragStartY = 0;
-let dragStartHeight = 0;
-
-function openTab(tab: Tab) {
-	activeTab = tab;
-	if (!open) {
-		open = true;
-		if (height <= MIN_HEIGHT) height = DEFAULT_HEIGHT;
-	}
-}
-
-function closePanel() {
-	open = false;
-}
-
-function onDragStart(e: PointerEvent) {
-	isDragging = true;
-	dragStartY = e.clientY;
-	dragStartHeight = open ? height : MIN_HEIGHT;
-	(e.currentTarget as HTMLElement).setPointerCapture(e.pointerId);
-}
-
-function onDragMove(e: PointerEvent) {
-	if (!isDragging) return;
-	const delta = dragStartY - e.clientY; // positive = dragging up = bigger panel
-	const newHeight = dragStartHeight + delta;
-	const maxHeight = Math.floor(window.innerHeight * 0.8);
-
-	if (newHeight <= MIN_HEIGHT + 20) {
-		// collapsed past threshold → close
-		open = false;
-	} else {
-		open = true;
-		height = Math.max(DEFAULT_HEIGHT / 4, Math.min(newHeight, maxHeight));
-	}
-}
-
-function onDragEnd() {
-	isDragging = false;
-}
-
-const tabs: { id: Tab; label: () => string }[] = [
-	{ id: 'metadata', label: m.doc_panel_tab_metadata },
-	{ id: 'transcription', label: m.doc_panel_tab_transcription },
-	{ id: 'discussion', label: m.doc_panel_tab_discussion },
-	{ id: 'history', label: m.doc_panel_tab_history }
-];
-
-const panelHeight = $derived(open ? height : MIN_HEIGHT);
-</script>
-
-<div
-	class="fixed right-0 bottom-0 left-0 z-30 flex flex-col border-t border-brand-sand bg-white shadow-[0_-4px_16px_rgba(0,0,0,0.08)]"
-	style="height: {panelHeight}px"
-	data-testid="bottom-panel"
->
-	<!-- Drag handle -->
-	<div
-		class="flex h-2 shrink-0 cursor-ns-resize items-center justify-center bg-white"
-		style="touch-action: none"
-		role="separator"
-		aria-orientation="horizontal"
-		aria-label="Panel resize"
-		onpointerdown={onDragStart}
-		onpointermove={onDragMove}
-		onpointerup={onDragEnd}
-		onpointercancel={onDragEnd}
-	>
-		<div class="h-1 w-12 rounded-full bg-gray-200"></div>
-	</div>
-
-	<!-- Tab bar -->
-	<div class="flex shrink-0 items-center border-b border-brand-sand bg-white px-4">
-		{#each tabs as tab (tab.id)}
-			<button
-				onclick={() => openTab(tab.id)}
-				class="mr-1 px-3 py-2.5 font-sans text-xs font-medium transition-colors {activeTab === tab.id && open
-					? 'border-b-2 border-brand-navy text-brand-navy'
-					: 'text-gray-400 hover:text-brand-navy'}"
-				aria-pressed={activeTab === tab.id && open}
-			>
-				{tab.label()}
-			</button>
-		{/each}
-
-		<!-- spacer -->
-		<div class="flex-1"></div>
-
-		{#if open}
-			<button
-				onclick={closePanel}
-				data-testid="panel-close-btn"
-				aria-label="Panel schließen"
-				class="rounded p-1.5 text-gray-400 transition-colors hover:bg-brand-sand/50 hover:text-brand-navy"
-			>
-				<svg class="h-4 w-4" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
-					<path stroke-linecap="round" stroke-linejoin="round" d="M6 18L18 6M6 6l12 12" />
-				</svg>
-			</button>
-		{/if}
-	</div>
-
-	<!-- Tab content -->
-	{#if open}
-		<div class="flex-1 overflow-y-auto" data-testid="bottom-panel-content">
-			{#if activeTab === 'metadata'}
-				<PanelMetadata doc={doc} />
-			{:else if activeTab === 'transcription'}
-				<PanelTranscription doc={doc} />
-			{:else if activeTab === 'discussion'}
-				<PanelDiscussion
-					documentId={doc.id}
-					activeAnnotationId={activeAnnotationId}
-					initialComments={comments}
-					canComment={canComment}
-					currentUserId={currentUserId}
-					canAdmin={canAdmin}
-					onAnnotationCommentCountChange={onAnnotationCommentCountChange}
-				/>
-			{:else if activeTab === 'history'}
-				<PanelHistory documentId={doc.id} />
-			{/if}
-		</div>
-	{/if}
-</div>

frontend/src/lib/components/DocumentTopBar.svelte

@@ -1,142 +0,0 @@
-<script lang="ts">
-import { m } from '$lib/paraglide/messages.js';
-
-type Person = { id: string; firstName: string; lastName: string };
-
-type Doc = {
-	id: string;
-	title?: string | null;
-	originalFilename?: string | null;
-	documentDate?: string | null;
-	sender?: Person | null;
-	receivers?: Person[] | null;
-	filePath?: string | null;
-	contentType?: string | null;
-};
-
-type Props = {
-	doc: Doc;
-	canWrite: boolean;
-	canAnnotate: boolean;
-	fileUrl: string;
-	annotateMode: boolean;
-};
-
-let { doc, canWrite, canAnnotate, fileUrl, annotateMode = $bindable() }: Props = $props();
-
-const isPdf = $derived(!!doc.filePath && doc.contentType?.startsWith('application/pdf'));
-
-const receiverDisplay = $derived.by(() => {
-	const receivers = doc.receivers ?? [];
-	if (receivers.length === 0) return null;
-	const shown = receivers.slice(0, 2);
-	const extra = receivers.length - shown.length;
-	const names = shown.map((r) => `${r.firstName} ${r.lastName}`).join(', ');
-	return extra > 0 ? `${names} +${extra}` : names;
-});
-
-const compactMeta = $derived.by(() => {
-	const parts: string[] = [];
-	if (doc.documentDate) {
-		parts.push(
-			new Intl.DateTimeFormat('de-DE', {
-				day: 'numeric',
-				month: 'numeric',
-				year: 'numeric'
-			}).format(new Date(doc.documentDate + 'T12:00:00'))
-		);
-	}
-	if (doc.sender) {
-		const senderName = `${doc.sender.firstName} ${doc.sender.lastName}`;
-		const receiver = receiverDisplay;
-		parts.push(receiver ? `${senderName} → ${receiver}` : senderName);
-	} else if (receiverDisplay) {
-		parts.push(`→ ${receiverDisplay}`);
-	}
-	return parts.join(' · ');
-});
-</script>
-
-<div
-	class="z-20 flex shrink-0 items-center justify-between border-b border-brand-sand bg-white px-6 py-3 shadow-sm"
->
-	<!-- Left: back + title -->
-	<div class="flex min-w-0 items-center gap-4 overflow-hidden">
-		<a
-			href="/"
-			class="group flex shrink-0 items-center gap-2 font-sans text-sm font-medium text-gray-500 transition-colors hover:text-brand-navy"
-		>
-			<div
-				class="flex h-8 w-8 items-center justify-center rounded-full bg-brand-sand transition-colors group-hover:bg-brand-mint"
-			>
-				<img
-					src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Arrow/Arrow-Left-MD.svg"
-					alt=""
-					aria-hidden="true"
-					class="h-4 w-4"
-				/>
-			</div>
-			<span class="hidden sm:inline">{m.btn_back()}</span>
-		</a>
-
-		<div class="min-w-0 border-l border-gray-200 pl-4">
-			<h1
-				class="truncate font-serif text-base leading-tight text-brand-navy"
-				title={doc.title ?? doc.originalFilename ?? ''}
-			>
-				{doc.title || doc.originalFilename}
-			</h1>
-			{#if compactMeta}
-				<p class="truncate font-sans text-xs text-gray-500" title={compactMeta}>
-					{compactMeta}
-				</p>
-			{/if}
-		</div>
-	</div>
-
-	<!-- Right: actions -->
-	<div class="ml-4 flex shrink-0 items-center gap-2 font-sans">
-		{#if canAnnotate && isPdf}
-			<button
-				onclick={() => (annotateMode = !annotateMode)}
-				aria-label={annotateMode ? m.doc_panel_annotate_stop() : m.doc_panel_annotate()}
-				class="rounded px-3 py-1.5 font-sans text-xs font-medium transition {annotateMode
-					? 'bg-brand-navy text-white'
-					: 'border border-brand-navy text-brand-navy hover:bg-brand-navy hover:text-white'}"
-			>
-				{annotateMode ? m.doc_panel_annotate_stop() : m.doc_panel_annotate()}
-			</button>
-		{/if}
-
-		{#if canWrite}
-			<a
-				href="/documents/{doc.id}/edit"
-				class="flex items-center gap-2 rounded border border-brand-navy bg-transparent px-3 py-1.5 text-xs font-medium text-brand-navy transition hover:bg-brand-navy hover:text-white"
-			>
-				<img
-					src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Edit-Content-MD.svg"
-					alt=""
-					aria-hidden="true"
-					class="h-4 w-4"
-				/>
-				{m.btn_edit()}
-			</a>
-		{/if}
-
-		{#if doc.filePath}
-			<a
-				href={fileUrl}
-				download={doc.originalFilename}
-				class="rounded border border-transparent bg-brand-sand/50 p-1.5 text-brand-navy transition hover:bg-brand-mint"
-				title={m.doc_download_title()}
-			>
-				<img
-					src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Download-MD.svg"
-					alt=""
-					aria-hidden="true"
-					class="h-5 w-5"
-				/>
-			</a>
-		{/if}
-	</div>
-</div>

frontend/src/lib/components/DocumentViewer.svelte

@@ -1,93 +0,0 @@
-<script lang="ts">
-import { m } from '$lib/paraglide/messages.js';
-import PdfViewer from './PdfViewer.svelte';
-
-type Doc = {
-	id: string;
-	filePath?: string | null;
-	contentType?: string | null;
-};
-
-type Props = {
-	doc: Doc;
-	fileUrl: string;
-	isLoading: boolean;
-	error: string;
-	annotateMode: boolean;
-	activeAnnotationId: string | null;
-	onAnnotationClick: (id: string) => void;
-};
-
-let {
-	doc,
-	fileUrl,
-	isLoading,
-	error,
-	annotateMode = $bindable(),
-	activeAnnotationId = $bindable(),
-	onAnnotationClick
-}: Props = $props();
-</script>
-
-<div class="absolute inset-0 bg-[#2A2A2A]">
-	{#if isLoading}
-		<div class="flex h-full flex-col items-center justify-center text-brand-mint">
-			<svg
-				class="mb-4 h-8 w-8 animate-spin"
-				xmlns="http://www.w3.org/2000/svg"
-				fill="none"
-				viewBox="0 0 24 24"
-			>
-				<circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"
-				></circle>
-				<path
-					class="opacity-75"
-					fill="currentColor"
-					d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"
-				></path>
-			</svg>
-			<span class="font-sans text-sm tracking-wide">{m.doc_loading()}</span>
-		</div>
-	{:else if error}
-		<div class="flex h-full flex-col items-center justify-center px-4 text-center text-gray-400">
-			<p class="mb-2 font-serif">{error}</p>
-			{#if doc.filePath}
-				<a
-					href="/api/documents/{doc.id}/file"
-					target="_blank"
-					class="text-sm underline hover:text-white"
-				>
-					{m.doc_download_link()}
-				</a>
-			{/if}
-		</div>
-	{:else if !doc.filePath}
-		<div class="flex h-full flex-col items-center justify-center text-gray-400">
-			<div class="mb-6 rounded-full bg-white/5 p-8">
-				<img
-					src="/degruyter-icons/Simple/Medium-24px/SVG/Action/PDF-Document-MD.svg"
-					alt=""
-					aria-hidden="true"
-					class="h-12 w-12 opacity-50 invert"
-				/>
-			</div>
-			<p class="font-sans text-sm tracking-wide uppercase">{m.doc_no_scan()}</p>
-		</div>
-	{:else if fileUrl && doc.contentType?.startsWith('application/pdf')}
-		<PdfViewer
-			url={fileUrl}
-			documentId={doc.id}
-			bind:annotateMode={annotateMode}
-			bind:activeAnnotationId={activeAnnotationId}
-			onAnnotationClick={onAnnotationClick}
-		/>
-	{:else if fileUrl}
-		<div class="flex h-full w-full items-center justify-center overflow-auto p-8">
-			<img
-				src={fileUrl}
-				alt={m.doc_image_alt()}
-				class="max-h-full max-w-full object-contain shadow-2xl"
-			/>
-		</div>
-	{/if}
-</div>

frontend/src/lib/components/PanelDiscussion.svelte

@@ -1,85 +0,0 @@
-<script lang="ts">
-import { m } from '$lib/paraglide/messages.js';
-import CommentThread from './CommentThread.svelte';
-
-type CommentReply = {
-	id: string;
-	authorId: string | null;
-	authorName: string;
-	content: string;
-	createdAt: string;
-	updatedAt: string;
-};
-
-type Comment = {
-	id: string;
-	authorId: string | null;
-	authorName: string;
-	content: string;
-	createdAt: string;
-	updatedAt: string;
-	replies: CommentReply[];
-};
-
-type Props = {
-	documentId: string;
-	activeAnnotationId: string | null;
-	initialComments: Comment[];
-	canComment: boolean;
-	currentUserId: string | null;
-	canAdmin: boolean;
-	onAnnotationCommentCountChange?: (annotationId: string, count: number) => void;
-};
-
-let {
-	documentId,
-	activeAnnotationId,
-	initialComments,
-	canComment,
-	currentUserId,
-	canAdmin,
-	onAnnotationCommentCountChange
-}: Props = $props();
-</script>
-
-<div class="space-y-8 p-6">
-	<!-- Annotation thread (shown when an annotation is active) -->
-	{#if activeAnnotationId}
-		<div>
-			<h4
-				class="mb-3 border-b border-brand-sand pb-2 font-sans text-xs font-bold tracking-widest text-brand-navy uppercase"
-			>
-				{m.doc_panel_annotation_thread_title()}
-			</h4>
-			{#key activeAnnotationId}
-				<CommentThread
-					documentId={documentId}
-					annotationId={activeAnnotationId}
-					canComment={canComment}
-					currentUserId={currentUserId}
-					canAdmin={canAdmin}
-					loadOnMount={true}
-					onCountChange={(count) => onAnnotationCommentCountChange?.(activeAnnotationId, count)}
-				/>
-			{/key}
-		</div>
-	{/if}
-
-	<!-- General document discussion -->
-	<div>
-		{#if activeAnnotationId}
-			<h4
-				class="mb-3 border-b border-brand-sand pb-2 font-sans text-xs font-bold tracking-widest text-brand-navy uppercase"
-			>
-				{m.comment_section_title()}
-			</h4>
-		{/if}
-		<CommentThread
-			documentId={documentId}
-			initialComments={initialComments}
-			canComment={canComment}
-			currentUserId={currentUserId}
-			canAdmin={canAdmin}
-		/>
-	</div>
-</div>

frontend/src/lib/components/PanelHistory.svelte

@@ -1,446 +0,0 @@
-<script lang="ts">
-import { m } from '$lib/paraglide/messages.js';
-import { diffWords } from 'diff';
-
-let { documentId }: { documentId: string } = $props();
-
-type VersionSummary = {
-	id: string;
-	savedAt: string;
-	editorName: string;
-	changedFields: string[];
-};
-
-type SnapshotDoc = {
-	title?: string;
-	documentDate?: string;
-	location?: string;
-	documentLocation?: string;
-	transcription?: string;
-	summary?: string;
-	sender?: { id: string; firstName: string; lastName: string } | null;
-	receivers?: { id: string; firstName: string; lastName: string }[];
-	tags?: { id: string; name: string }[];
-};
-
-type DiffEntry =
-	| {
-			kind: 'text';
-			field: string;
-			label: string;
-			parts: { value: string; added?: boolean; removed?: boolean }[];
-	  }
-	| { kind: 'scalar'; field: string; label: string; oldVal: string; newVal: string }
-	| { kind: 'relation'; field: string; label: string; removed: string[]; added: string[] };
-
-let historyLoaded = $state(false);
-let historyLoading = $state(false);
-let versions = $state<VersionSummary[]>([]);
-
-let compareMode = $state(false);
-let compareA = $state('');
-let compareB = $state('');
-
-let selectedVersionId = $state<string | null>(null);
-let diffEntries = $state<DiffEntry[]>([]);
-let diffLoading = $state(false);
-let noDiff = $state(false);
-
-const fieldLabels: Record<string, () => string> = {
-	title: m.history_field_title,
-	documentDate: m.history_field_document_date,
-	location: m.history_field_location,
-	documentLocation: m.history_field_document_location,
-	transcription: m.history_field_transcription,
-	summary: m.history_field_summary,
-	sender: m.history_field_sender,
-	receivers: m.history_field_receivers,
-	tags: m.history_field_tags
-};
-
-const TEXT_FIELDS = ['title', 'summary', 'transcription'] as const;
-const SCALAR_FIELDS = ['documentDate', 'location', 'documentLocation'] as const;
-
-function parseSnapshot(raw: string): SnapshotDoc {
-	try {
-		return JSON.parse(raw) as SnapshotDoc;
-	} catch {
-		return {};
-	}
-}
-
-function personLabel(p: { firstName: string; lastName: string }): string {
-	return `${p.firstName} ${p.lastName}`.trim();
-}
-
-const DIFF_CONTEXT_WORDS = 4;
-
-type DiffPart = { value: string; added?: boolean; removed?: boolean };
-
-function trimContextParts(parts: DiffPart[]): DiffPart[] {
-	return parts.flatMap((part, i) => {
-		if (part.added || part.removed) return [part];
-		const tokens = part.value.split(/(\s+)/).filter(Boolean);
-		const wordCount = tokens.filter((t) => /\S/.test(t)).length;
-		if (wordCount <= DIFF_CONTEXT_WORDS * 2) return [part];
-
-		function keepFirst(n: number): string {
-			let count = 0;
-			const out: string[] = [];
-			for (const t of tokens) {
-				out.push(t);
-				if (/\S/.test(t) && ++count >= n) break;
-			}
-			return out.join('');
-		}
-		function keepLast(n: number): string {
-			let count = 0;
-			const out: string[] = [];
-			for (const t of [...tokens].reverse()) {
-				out.unshift(t);
-				if (/\S/.test(t) && ++count >= n) break;
-			}
-			return out.join('');
-		}
-
-		const isFirst = i === 0;
-		const isLast = i === parts.length - 1;
-		if (isFirst) return [{ value: '… ' + keepLast(DIFF_CONTEXT_WORDS) }];
-		if (isLast) return [{ value: keepFirst(DIFF_CONTEXT_WORDS) + ' …' }];
-		return [{ value: keepFirst(DIFF_CONTEXT_WORDS) + ' … ' + keepLast(DIFF_CONTEXT_WORDS) }];
-	});
-}
-
-function buildDiff(older: SnapshotDoc | null, newer: SnapshotDoc): DiffEntry[] {
-	const entries: DiffEntry[] = [];
-
-	for (const field of TEXT_FIELDS) {
-		const a = older?.[field] ?? '';
-		const b = newer[field] ?? '';
-		if (a === b) continue;
-		const parts = trimContextParts(diffWords(a, b));
-		entries.push({ kind: 'text', field, label: fieldLabels[field](), parts });
-	}
-
-	for (const field of SCALAR_FIELDS) {
-		const a = older?.[field] ?? '';
-		const b = newer[field] ?? '';
-		if (a === b) continue;
-		entries.push({ kind: 'scalar', field, label: fieldLabels[field](), oldVal: a, newVal: b });
-	}
-
-	const senderA = older?.sender ? personLabel(older.sender) : '';
-	const senderB = newer.sender ? personLabel(newer.sender) : '';
-	if (senderA !== senderB) {
-		entries.push({
-			kind: 'relation',
-			field: 'sender',
-			label: fieldLabels['sender'](),
-			removed: senderA ? [senderA] : [],
-			added: senderB ? [senderB] : []
-		});
-	}
-
-	const receiversA = new Set((older?.receivers ?? []).map(personLabel));
-	const receiversB = new Set((newer.receivers ?? []).map(personLabel));
-	const removedReceivers = [...receiversA].filter((r) => !receiversB.has(r));
-	const addedReceivers = [...receiversB].filter((r) => !receiversA.has(r));
-	if (removedReceivers.length > 0 || addedReceivers.length > 0) {
-		entries.push({
-			kind: 'relation',
-			field: 'receivers',
-			label: fieldLabels['receivers'](),
-			removed: removedReceivers,
-			added: addedReceivers
-		});
-	}
-
-	const tagsA = new Set((older?.tags ?? []).map((t) => t.name));
-	const tagsB = new Set((newer.tags ?? []).map((t) => t.name));
-	const removedTags = [...tagsA].filter((t) => !tagsB.has(t));
-	const addedTags = [...tagsB].filter((t) => !tagsA.has(t));
-	if (removedTags.length > 0 || addedTags.length > 0) {
-		entries.push({
-			kind: 'relation',
-			field: 'tags',
-			label: fieldLabels['tags'](),
-			removed: removedTags,
-			added: addedTags
-		});
-	}
-
-	return entries;
-}
-
-async function fetchSnapshot(versionId: string): Promise<SnapshotDoc> {
-	const res = await fetch(`/api/documents/${documentId}/versions/${versionId}`);
-	if (!res.ok) throw new Error('Failed to fetch version');
-	const v = await res.json();
-	return parseSnapshot(v.snapshot);
-}
-
-async function loadHistory() {
-	if (historyLoaded) return;
-	historyLoading = true;
-	try {
-		const res = await fetch(`/api/documents/${documentId}/versions`);
-		if (res.ok) {
-			versions = await res.json();
-		}
-		historyLoaded = true;
-	} catch {
-		// ignore
-	} finally {
-		historyLoading = false;
-	}
-}
-
-async function selectVersion(versionId: string) {
-	if (selectedVersionId === versionId) {
-		selectedVersionId = null;
-		diffEntries = [];
-		noDiff = false;
-		return;
-	}
-	selectedVersionId = versionId;
-	diffEntries = [];
-	noDiff = false;
-	diffLoading = true;
-	try {
-		const idx = versions.findIndex((v) => v.id === versionId);
-		const newerSnap = await fetchSnapshot(versionId);
-		const olderSnap = idx > 0 ? await fetchSnapshot(versions[idx - 1].id) : null;
-		const entries = buildDiff(olderSnap, newerSnap);
-		if (entries.length === 0) {
-			noDiff = true;
-		} else {
-			diffEntries = entries;
-		}
-	} catch {
-		// ignore
-	} finally {
-		diffLoading = false;
-	}
-}
-
-async function applyCompare() {
-	if (!compareA || !compareB || compareA === compareB) return;
-	selectedVersionId = null;
-	diffEntries = [];
-	noDiff = false;
-	diffLoading = true;
-	try {
-		const [snapA, snapB] = await Promise.all([fetchSnapshot(compareA), fetchSnapshot(compareB)]);
-		const entries = buildDiff(snapA, snapB);
-		if (entries.length === 0) {
-			noDiff = true;
-		} else {
-			diffEntries = entries;
-		}
-	} catch {
-		// ignore
-	} finally {
-		diffLoading = false;
-	}
-}
-
-function formatDateTime(iso: string): string {
-	try {
-		return new Intl.DateTimeFormat('de-DE', {
-			day: 'numeric',
-			month: 'short',
-			year: 'numeric',
-			hour: '2-digit',
-			minute: '2-digit'
-		}).format(new Date(iso));
-	} catch {
-		return iso;
-	}
-}
-
-function versionLabel(v: VersionSummary, index: number): string {
-	return `Version ${index + 1} — ${v.editorName} — ${formatDateTime(v.savedAt)}`;
-}
-
-// Load history when this panel mounts.
-$effect(() => {
-	loadHistory();
-});
-</script>
-
-<div class="space-y-4 p-6">
-	{#if historyLoading}
-		<p class="font-sans text-xs text-gray-400">{m.history_loading()}</p>
-	{:else if !historyLoaded}
-		<!-- initial state before effect runs — show nothing -->
-	{:else if versions.length === 0}
-		<p class="font-serif text-sm text-gray-400 italic">{m.history_empty()}</p>
-	{:else}
-		<!-- Compare mode toggle -->
-		<div class="flex justify-end">
-			<button
-				onclick={() => {
-					compareMode = !compareMode;
-					diffEntries = [];
-					noDiff = false;
-					selectedVersionId = null;
-				}}
-				class="font-sans text-xs font-medium transition {compareMode
-					? 'text-brand-navy underline'
-					: 'text-gray-400 hover:text-brand-navy'}"
-			>
-				{m.history_compare_mode()}
-			</button>
-		</div>
-
-		{#if compareMode}
-			<div class="space-y-2">
-				<div>
-					<label for="compare-a" class="mb-1 block font-sans text-[10px] text-gray-400 uppercase"
-						>{m.history_compare_select_a()}</label
-					>
-					<select
-						id="compare-a"
-						bind:value={compareA}
-						class="w-full rounded border border-brand-sand bg-white px-2 py-1 font-sans text-xs text-brand-navy focus:ring-1 focus:ring-brand-mint focus:outline-none"
-					>
-						<option value="">—</option>
-						{#each versions as v, i (v.id)}
-							<option value={v.id}>{versionLabel(v, i)}</option>
-						{/each}
-					</select>
-				</div>
-				<div>
-					<label for="compare-b" class="mb-1 block font-sans text-[10px] text-gray-400 uppercase"
-						>{m.history_compare_select_b()}</label
-					>
-					<select
-						id="compare-b"
-						bind:value={compareB}
-						class="w-full rounded border border-brand-sand bg-white px-2 py-1 font-sans text-xs text-brand-navy focus:ring-1 focus:ring-brand-mint focus:outline-none"
-					>
-						<option value="">—</option>
-						{#each versions as v, i (v.id)}
-							<option value={v.id}>{versionLabel(v, i)}</option>
-						{/each}
-					</select>
-				</div>
-				<button
-					onclick={applyCompare}
-					disabled={!compareA || !compareB || compareA === compareB}
-					class="w-full rounded bg-brand-navy px-3 py-1.5 font-sans text-xs font-medium text-white transition hover:bg-brand-navy/80 disabled:cursor-not-allowed disabled:opacity-40"
-				>
-					{m.history_compare_apply()}
-				</button>
-			</div>
-		{:else}
-			<!-- Version list -->
-			<ul class="divide-y divide-brand-sand">
-				{#each versions as v, i (v.id)}
-					<li>
-						<button
-							onclick={() => selectVersion(v.id)}
-							data-testid="history-version"
-							class="w-full py-2 text-left transition hover:bg-brand-sand/30 {selectedVersionId ===
-							v.id
-								? 'border-l-2 border-brand-mint pl-2'
-								: 'pl-0'}"
-						>
-							<div class="flex items-baseline justify-between gap-2">
-								<span class="font-sans text-xs font-medium text-brand-navy">
-									Version {i + 1}
-								</span>
-								<span class="font-sans text-[10px] text-gray-400">
-									{formatDateTime(v.savedAt)}
-								</span>
-							</div>
-							<span class="font-sans text-[11px] text-gray-500">{v.editorName}</span>
-							{#if v.changedFields && v.changedFields.length > 0}
-								<div class="mt-1 flex flex-wrap gap-1">
-									{#each v.changedFields as field (field)}
-										<span
-											class="rounded bg-brand-sand/50 px-1.5 py-0.5 font-sans text-[10px] tracking-wide text-gray-500 uppercase"
-										>
-											{fieldLabels[field] ? fieldLabels[field]() : field}
-										</span>
-									{/each}
-								</div>
-							{/if}
-						</button>
-					</li>
-				{/each}
-			</ul>
-		{/if}
-
-		<!-- Diff panel -->
-		{#if diffLoading}
-			<p class="font-sans text-xs text-gray-400">{m.history_loading()}</p>
-		{:else if noDiff}
-			<div
-				data-testid="history-diff"
-				class="rounded-sm border border-brand-sand bg-white p-4 font-serif text-sm text-gray-400 italic"
-			>
-				{m.history_diff_no_changes()}
-			</div>
-		{:else if diffEntries.length > 0}
-			<div
-				data-testid="history-diff"
-				class="space-y-4 rounded-sm border border-brand-sand bg-white p-4"
-			>
-				{#each diffEntries as entry (entry.field)}
-					<div>
-						<span
-							class="mb-1.5 block font-sans text-[10px] font-bold tracking-wide text-gray-400 uppercase"
-							>{entry.label}</span
-						>
-						{#if entry.kind === 'text'}
-							<p class="font-serif text-sm leading-relaxed">
-								{#each entry.parts as part, partIdx (partIdx)}
-									{#if part.added}
-										<span class="bg-green-50 text-green-700">{part.value}</span>
-									{:else if part.removed}
-										<span class="bg-red-50 text-red-600 line-through">{part.value}</span>
-									{:else}
-										<span>{part.value}</span>
-									{/if}
-								{/each}
-							</p>
-						{:else if entry.kind === 'scalar'}
-							<div class="flex items-center gap-2 font-serif text-sm">
-								<span class="text-red-600 line-through">{entry.oldVal || '—'}</span>
-								<svg
-									class="h-3 w-3 flex-shrink-0 text-gray-400"
-									viewBox="0 0 20 20"
-									fill="currentColor"
-									aria-hidden="true"
-								>
-									<path
-										fill-rule="evenodd"
-										d="M10.293 3.293a1 1 0 011.414 0l6 6a1 1 0 010 1.414l-6 6a1 1 0 01-1.414-1.414L14.586 11H3a1 1 0 110-2h11.586l-4.293-4.293a1 1 0 010-1.414z"
-										clip-rule="evenodd"
-									/>
-								</svg>
-								<span class="text-green-700">{entry.newVal || '—'}</span>
-							</div>
-						{:else if entry.kind === 'relation'}
-							<div class="flex flex-wrap gap-1.5">
-								{#each entry.removed as item (item)}
-									<span
-										class="rounded bg-red-50 px-1.5 py-0.5 font-sans text-[11px] text-red-600 line-through"
-										>{item}</span
-									>
-								{/each}
-								{#each entry.added as item (item)}
-									<span
-										class="rounded bg-green-50 px-1.5 py-0.5 font-sans text-[11px] text-green-700"
-										>{item}</span
-									>
-								{/each}
-							</div>
-						{/if}
-					</div>
-				{/each}
-			</div>
-		{/if}
-	{/if}
-</div>

frontend/src/lib/components/PanelMetadata.svelte

@@ -1,202 +0,0 @@
-<script lang="ts">
-import { m } from '$lib/paraglide/messages.js';
-import { formatDate } from '$lib/utils/date';
-
-type Person = { id: string; firstName: string; lastName: string; alias?: string | null };
-type Tag = { id: string; name: string };
-
-type Doc = {
-	documentDate?: string | null;
-	location?: string | null;
-	documentLocation?: string | null;
-	tags?: Tag[] | null;
-	sender?: Person | null;
-	receivers?: Person[] | null;
-};
-
-let { doc }: { doc: Doc } = $props();
-</script>
-
-<div class="space-y-10 p-6">
-	<!-- DETAILS GROUP -->
-	<div>
-		<h3
-			class="mb-4 border-b border-brand-sand pb-2 font-sans text-xs font-bold tracking-widest text-brand-navy uppercase"
-		>
-			{m.doc_section_details()}
-		</h3>
-		<div class="space-y-5">
-			<!-- Date -->
-			<div class="flex items-start">
-				<span class="mt-0.5 w-8 text-brand-mint">
-					<img
-						src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Calendar/Calendar-Add-MD.svg"
-						alt=""
-						aria-hidden="true"
-						class="h-5 w-5"
-					/>
-				</span>
-				<div>
-					<span class="block font-serif text-lg text-brand-navy">
-						{doc.documentDate ? formatDate(doc.documentDate) : '—'}
-					</span>
-					<span class="font-sans text-xs text-gray-500">{m.doc_label_document_date()}</span>
-				</div>
-			</div>
-
-			<!-- Creation Location -->
-			<div class="flex items-start">
-				<span class="mt-0.5 w-8 text-brand-mint">
-					<img
-						src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Location-MD.svg"
-						alt=""
-						aria-hidden="true"
-						class="h-5 w-5"
-					/>
-				</span>
-				<div>
-					<span class="block font-serif text-lg text-brand-navy">
-						{doc.location ? doc.location : '—'}
-					</span>
-					<span class="font-sans text-xs text-gray-500">{m.doc_label_creation_location()}</span>
-				</div>
-			</div>
-
-			<!-- Physical Archive Location -->
-			{#if doc.documentLocation}
-				<div class="flex items-start">
-					<span class="mt-0.5 w-8 text-brand-mint">
-						<img
-							src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Folder-MD.svg"
-							alt=""
-							aria-hidden="true"
-							class="h-5 w-5"
-						/>
-					</span>
-					<div>
-						<span class="block font-serif text-lg text-brand-navy">
-							{doc.documentLocation}
-						</span>
-						<span class="font-sans text-xs text-gray-500"
-							>{m.doc_label_archive_location_original()}</span
-						>
-					</div>
-				</div>
-			{/if}
-
-			<!-- Tags -->
-			{#if doc.tags && doc.tags.length > 0}
-				<div class="flex items-start">
-					<span class="mt-0.5 w-8 text-brand-mint">
-						<img
-							src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Bookmark/Bookmark-Outline-MD.svg"
-							alt=""
-							aria-hidden="true"
-							class="h-5 w-5"
-						/>
-					</span>
-					<div class="flex-1">
-						<div class="mb-1 flex flex-wrap gap-2">
-							{#each doc.tags as tag (tag.id)}
-								<a
-									href="/?tag={encodeURIComponent(tag.name)}"
-									class="inline-flex items-center rounded bg-brand-sand/50 px-2 py-0.5 text-xs font-bold tracking-wide text-brand-navy uppercase transition-colors hover:bg-brand-navy hover:text-white"
-									title={m.doc_tag_filter_title({ name: tag.name })}
-								>
-									{tag.name}
-								</a>
-							{/each}
-						</div>
-						<span class="font-sans text-xs text-gray-500">{m.form_label_tags()}</span>
-					</div>
-				</div>
-			{/if}
-		</div>
-	</div>
-
-	<!-- PERSONEN GROUP -->
-	<div>
-		<h3
-			class="mb-4 border-b border-brand-sand pb-2 font-sans text-xs font-bold tracking-widest text-brand-navy uppercase"
-		>
-			{m.doc_section_persons()}
-		</h3>
-
-		<div class="mb-6">
-			<span class="mb-2 block font-sans text-xs text-gray-400 uppercase"
-				>{m.form_label_sender()}</span
-			>
-			{#if doc.sender}
-				<a
-					href="/persons/{doc.sender.id}"
-					class="group block rounded border border-brand-sand bg-brand-sand/20 p-3 transition hover:border-brand-mint hover:bg-brand-mint/10"
-				>
-					<div class="flex items-center gap-3">
-						<div
-							class="flex h-8 w-8 items-center justify-center rounded-full bg-brand-navy font-serif text-sm text-white"
-						>
-							{doc.sender.firstName[0]}{doc.sender.lastName[0]}
-						</div>
-						<div>
-							<p
-								class="font-serif text-brand-navy decoration-brand-mint underline-offset-2 group-hover:underline"
-							>
-								{doc.sender.firstName}
-								{doc.sender.lastName}
-							</p>
-							{#if doc.sender.alias}
-								<p class="font-sans text-xs text-gray-500">{doc.sender.alias}</p>
-							{/if}
-						</div>
-					</div>
-				</a>
-			{:else}
-				<span class="font-serif text-sm text-gray-400 italic">{m.doc_sender_not_specified()}</span>
-			{/if}
-		</div>
-
-		<div>
-			<span class="mb-2 block font-sans text-xs text-gray-400 uppercase"
-				>{m.form_label_receivers()}</span
-			>
-			{#if doc.receivers && doc.receivers.length > 0}
-				<div class="space-y-2">
-					{#each doc.receivers as receiver (receiver.id)}
-						<div
-							class="group flex items-center justify-between rounded border border-brand-sand bg-white p-3 transition hover:border-brand-navy"
-						>
-							<a href="/persons/{receiver.id}" class="flex min-w-0 flex-1 items-center gap-3">
-								<div
-									class="flex h-6 w-6 items-center justify-center rounded-full bg-gray-100 font-serif text-xs text-gray-500"
-								>
-									{receiver.firstName[0]}{receiver.lastName[0]}
-								</div>
-								<span class="truncate font-serif text-sm text-brand-navy">
-									{receiver.firstName}
-									{receiver.lastName}
-								</span>
-							</a>
-
-							{#if doc.sender}
-								<a
-									href="/conversations?senderId={doc.sender.id}&receiverId={receiver.id}"
-									class="text-gray-300 transition hover:text-brand-mint"
-									title={m.doc_conversation_title()}
-								>
-									<img
-										src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Chat-MD.svg"
-										alt=""
-										aria-hidden="true"
-										class="h-5 w-5"
-									/>
-								</a>
-							{/if}
-						</div>
-					{/each}
-				</div>
-			{:else}
-				<span class="font-serif text-sm text-gray-400 italic">{m.doc_no_receivers()}</span>
-			{/if}
-		</div>
-	</div>
-</div>

frontend/src/lib/components/PanelTranscription.svelte

@@ -1,42 +0,0 @@
-<script lang="ts">
-import { m } from '$lib/paraglide/messages.js';
-
-type Doc = {
-	summary?: string | null;
-	transcription?: string | null;
-};
-
-let { doc }: { doc: Doc } = $props();
-</script>
-
-<div class="flex justify-center px-6 py-8">
-	<div class="w-full max-w-prose space-y-8">
-		{#if !doc.summary && !doc.transcription}
-			<p class="font-serif text-sm text-gray-400 italic">—</p>
-		{/if}
-
-		{#if doc.summary}
-			<div>
-				<span
-					class="mb-3 block font-sans text-xs font-bold tracking-widest text-gray-400 uppercase"
-				>
-					{m.doc_label_summary()}
-				</span>
-				<p class="font-serif text-base leading-relaxed text-brand-navy">{doc.summary}</p>
-			</div>
-		{/if}
-
-		{#if doc.transcription}
-			<div>
-				<span
-					class="mb-3 block font-sans text-xs font-bold tracking-widest text-gray-400 uppercase"
-				>
-					{m.form_label_transcription()}
-				</span>
-				<p class="font-serif text-base leading-relaxed whitespace-pre-wrap text-brand-navy">
-					{doc.transcription}
-				</p>
-			</div>
-		{/if}
-	</div>
-</div>

frontend/src/lib/components/PdfViewer.svelte

@@ -3,19 +3,25 @@ import { onMount } from 'svelte';
 import { SvelteMap } from 'svelte/reactivity';
 import type { PDFDocumentProxy, PDFPageProxy, RenderTask } from 'pdfjs-dist';
 import AnnotationLayer from './AnnotationLayer.svelte';
+import AnnotationCommentPanel from './AnnotationCommentPanel.svelte';
+import { m } from '$lib/paraglide/messages.js';
 
 let {
 	url,
 	documentId = '',
-	annotateMode = $bindable(false),
-	activeAnnotationId = $bindable<string | null>(null),
-	onAnnotationClick
+	canAnnotate = false,
+	canComment,
+	currentUserId,
+	canAdmin,
+	documentFileHash
 }: {
 	url: string;
 	documentId?: string;
-	annotateMode?: boolean;
-	activeAnnotationId?: string | null;
-	onAnnotationClick?: (id: string) => void;
+	canAnnotate?: boolean;
+	canComment?: boolean;
+	currentUserId?: string | null;
+	canAdmin?: boolean;
+	documentFileHash?: string | null;
 } = $props();
 
 let pdfDoc = $state<PDFDocumentProxy | null>(null);
@@ -48,11 +54,19 @@ type Annotation = {
 	height: number;
 	color: string;
 	createdAt: string;
+	fileHash?: string | null;
 };
 
 let annotations = $state<Annotation[]>([]);
+let annotateMode = $state(false);
 let annotateColor = $state('#ffff00');
 let commentCounts = new SvelteMap<string, number>();
+let activeAnnotationId = $state<string | null>(null);
+
+const visibleAnnotations = $derived(
+	annotations.filter((a) => !a.fileHash || !documentFileHash || a.fileHash === documentFileHash)
+);
+const outdatedCount = $derived(annotations.length - visibleAnnotations.length);
 
 onMount(async () => {
 	// Dynamic import keeps pdfjs out of the SSR bundle entirely
@@ -213,7 +227,6 @@ async function handleAnnotationDraw(rect: { x: number; y: number; width: number;
 			const created: Annotation = await res.json();
 			annotations = [...annotations, created];
 			activeAnnotationId = created.id;
-			onAnnotationClick?.(created.id);
 		}
 	} catch {
 		// ignore
@@ -234,11 +247,6 @@ async function handleAnnotationDelete(annotationId: string) {
 	}
 }
 
-function handleAnnotationClick(id: string) {
-	activeAnnotationId = id;
-	onAnnotationClick?.(id);
-}
-
 $effect(() => {
 	if (pdfjsReady && url) {
 		loadDocument(url);
@@ -299,6 +307,27 @@ function zoomOut() {
 	</div>
 {:else}
 	<div class="flex h-full w-full flex-col bg-[#2A2A2A]">
+		{#if outdatedCount > 0}
+			<div
+				class="flex shrink-0 items-center gap-2 border-b border-amber-500/30 bg-amber-500/10 px-4 py-2"
+				data-testid="annotation-outdated-notice"
+			>
+				<svg
+					class="h-4 w-4 shrink-0 text-amber-400"
+					viewBox="0 0 24 24"
+					fill="none"
+					stroke="currentColor"
+					stroke-width="2"
+				>
+					<path
+						stroke-linecap="round"
+						stroke-linejoin="round"
+						d="M12 9v3.75m-9.303 3.376c-.866 1.5.217 3.374 1.948 3.374h14.71c1.73 0 2.813-1.874 1.948-3.374L13.949 3.378c-.866-1.5-3.032-1.5-3.898 0L2.697 16.126zM12 15.75h.007v.008H12v-.008z"
+					/>
+				</svg>
+				<span class="font-sans text-xs text-amber-300">{m.annotation_outdated_notice()}</span>
+			</div>
+		{/if}
 		<!-- Controls -->
 		<div
 			class="flex shrink-0 items-center justify-between gap-2 border-b border-white/10 px-4 py-2"
@@ -386,15 +415,35 @@ function zoomOut() {
 				</button>
 			</div>
 
-			<!-- Color picker (shown in annotate mode) -->
-			{#if annotateMode}
-				<input
-					type="color"
-					bind:value={annotateColor}
-					aria-label="Farbe wählen"
-					class="h-6 w-6 cursor-pointer rounded border-0 bg-transparent p-0"
-					title="Farbe wählen"
-				/>
+			<!-- Annotate controls -->
+			{#if canAnnotate}
+				<div class="flex items-center gap-1">
+					<button
+						onclick={() => (annotateMode = !annotateMode)}
+						aria-label={annotateMode ? 'Annotieren beenden' : 'Annotieren'}
+						class="rounded px-2 py-1 font-sans text-xs text-gray-300 transition hover:bg-white/10 {annotateMode ? 'bg-white/20' : ''}"
+					>
+						{annotateMode ? 'Fertig' : 'Annotieren'}
+					</button>
+					{#if annotateMode}
+						<input
+							type="color"
+							bind:value={annotateColor}
+							aria-label="Farbe wählen"
+							class="h-6 w-6 cursor-pointer rounded border-0 bg-transparent p-0"
+							title="Farbe wählen"
+						/>
+					{/if}
+				</div>
+			{:else}
+				<button
+					disabled
+					title="Sie benötigen die Berechtigung ANNOTATE_ALL zum Annotieren"
+					class="cursor-not-allowed rounded px-2 py-1 font-sans text-xs text-gray-500"
+					aria-label="Annotieren (keine Berechtigung)"
+				>
+					Annotieren
+				</button>
 			{/if}
 		</div>
 
@@ -420,17 +469,33 @@ function zoomOut() {
 							style="position: absolute; top: 0; left: 0; overflow: hidden; pointer-events: none; line-height: 1;"
 						></div>
 						<AnnotationLayer
-							annotations={annotations.filter((a) => a.pageNumber === currentPage)}
+							annotations={visibleAnnotations.filter((a) => a.pageNumber === currentPage)}
 							canAnnotate={annotateMode}
 							color={annotateColor}
 							onDraw={handleAnnotationDraw}
 							onDelete={handleAnnotationDelete}
 							commentCounts={Object.fromEntries(commentCounts)}
-							onAnnotationClick={handleAnnotationClick}
+							onAnnotationClick={(id) => (activeAnnotationId = id)}
 						/>
 					</div>
 				</div>
 			{/if}
 		</div>
+
+		{#key activeAnnotationId}
+			{#if activeAnnotationId}
+				<AnnotationCommentPanel
+					documentId={documentId}
+					annotationId={activeAnnotationId}
+					canComment={canComment ?? false}
+					currentUserId={currentUserId ?? null}
+					canAdmin={canAdmin ?? false}
+					onClose={() => (activeAnnotationId = null)}
+					onCountChange={(count) => {
+						if (activeAnnotationId) commentCounts.set(activeAnnotationId, count);
+					}}
+				/>
+			{/if}
+		{/key}
 	</div>
 {/if}

frontend/src/lib/generated/api.ts

@@ -180,6 +180,86 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/api/documents/{documentId}/comments": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get: operations["getDocumentComments"];
+        put?: never;
+        post: operations["postDocumentComment"];
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
+    "/api/documents/{documentId}/comments/{commentId}/replies": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put?: never;
+        post: operations["replyToDocumentComment"];
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
+    "/api/documents/{documentId}/annotations": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get: operations["listAnnotations"];
+        put?: never;
+        post: operations["createAnnotation"];
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
+    "/api/documents/{documentId}/annotations/{annotationId}/comments": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get: operations["getAnnotationComments"];
+        put?: never;
+        post: operations["postAnnotationComment"];
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
+    "/api/documents/{documentId}/annotations/{annotationId}/comments/{commentId}/replies": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put?: never;
+        post: operations["replyToAnnotationComment"];
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/api/auth/reset-password": {
         parameters: {
             query?: never;
@@ -260,6 +340,22 @@ export interface paths {
         patch: operations["updateGroup"];
         trace?: never;
     };
+    "/api/documents/{documentId}/comments/{commentId}": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put?: never;
+        post?: never;
+        delete: operations["deleteComment"];
+        options?: never;
+        head?: never;
+        patch: operations["editComment"];
+        trace?: never;
+    };
     "/api/tags": {
         parameters: {
             query?: never;
@@ -420,6 +516,22 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/api/documents/{documentId}/annotations/{annotationId}": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put?: never;
+        post?: never;
+        delete: operations["deleteAnnotation"];
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
 }
 export type webhooks = Record<string, never>;
 export interface components {
@@ -510,6 +622,7 @@ export interface components {
             title: string;
             filePath?: string;
             contentType?: string;
+            fileHash?: string;
             originalFilename: string;
             /** @enum {string} */
             status: "PLACEHOLDER" | "UPLOADED" | "TRANSCRIBED" | "REVIEWED" | "ARCHIVED";
@@ -548,6 +661,63 @@ export interface components {
             name?: string;
             permissions?: string[];
         };
+        CreateCommentDTO: {
+            content?: string;
+        };
+        DocumentComment: {
+            /** Format: uuid */
+            id: string;
+            /** Format: uuid */
+            documentId: string;
+            /** Format: uuid */
+            annotationId?: string;
+            /** Format: uuid */
+            parentId?: string;
+            /** Format: uuid */
+            authorId?: string;
+            authorName: string;
+            content: string;
+            /** Format: date-time */
+            createdAt: string;
+            /** Format: date-time */
+            updatedAt: string;
+            replies: components["schemas"]["DocumentComment"][];
+        };
+        CreateAnnotationDTO: {
+            /** Format: int32 */
+            pageNumber?: number;
+            /** Format: double */
+            x?: number;
+            /** Format: double */
+            y?: number;
+            /** Format: double */
+            width?: number;
+            /** Format: double */
+            height?: number;
+            color?: string;
+        };
+        DocumentAnnotation: {
+            /** Format: uuid */
+            id: string;
+            /** Format: uuid */
+            documentId: string;
+            /** Format: int32 */
+            pageNumber: number;
+            /** Format: double */
+            x: number;
+            /** Format: double */
+            y: number;
+            /** Format: double */
+            width: number;
+            /** Format: double */
+            height: number;
+            color: string;
+            fileHash?: string;
+            /** Format: uuid */
+            createdBy?: string;
+            /** Format: date-time */
+            createdAt: string;
+        };
         ResetPasswordRequest: {
             token?: string;
             newPassword?: string;
@@ -1062,6 +1232,205 @@ export interface operations {
             };
         };
     };
+    getDocumentComments: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                documentId: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description OK */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "*/*": components["schemas"]["DocumentComment"][];
+                };
+            };
+        };
+    };
+    postDocumentComment: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                documentId: string;
+            };
+            cookie?: never;
+        };
+        requestBody: {
+            content: {
+                "application/json": components["schemas"]["CreateCommentDTO"];
+            };
+        };
+        responses: {
+            /** @description Created */
+            201: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "*/*": components["schemas"]["DocumentComment"];
+                };
+            };
+        };
+    };
+    replyToDocumentComment: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                documentId: string;
+                commentId: string;
+            };
+            cookie?: never;
+        };
+        requestBody: {
+            content: {
+                "application/json": components["schemas"]["CreateCommentDTO"];
+            };
+        };
+        responses: {
+            /** @description Created */
+            201: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "*/*": components["schemas"]["DocumentComment"];
+                };
+            };
+        };
+    };
+    listAnnotations: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                documentId: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description OK */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "*/*": components["schemas"]["DocumentAnnotation"][];
+                };
+            };
+        };
+    };
+    createAnnotation: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                documentId: string;
+            };
+            cookie?: never;
+        };
+        requestBody: {
+            content: {
+                "application/json": components["schemas"]["CreateAnnotationDTO"];
+            };
+        };
+        responses: {
+            /** @description Created */
+            201: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "*/*": components["schemas"]["DocumentAnnotation"];
+                };
+            };
+        };
+    };
+    getAnnotationComments: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                annotationId: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description OK */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "*/*": components["schemas"]["DocumentComment"][];
+                };
+            };
+        };
+    };
+    postAnnotationComment: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                documentId: string;
+                annotationId: string;
+            };
+            cookie?: never;
+        };
+        requestBody: {
+            content: {
+                "application/json": components["schemas"]["CreateCommentDTO"];
+            };
+        };
+        responses: {
+            /** @description Created */
+            201: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "*/*": components["schemas"]["DocumentComment"];
+                };
+            };
+        };
+    };
+    replyToAnnotationComment: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                documentId: string;
+                commentId: string;
+            };
+            cookie?: never;
+        };
+        requestBody: {
+            content: {
+                "application/json": components["schemas"]["CreateCommentDTO"];
+            };
+        };
+        responses: {
+            /** @description Created */
+            201: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "*/*": components["schemas"]["DocumentComment"];
+                };
+            };
+        };
+    };
     resetPassword: {
         parameters: {
             query?: never;
@@ -1192,6 +1561,54 @@ export interface operations {
             };
         };
     };
+    deleteComment: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                documentId: string;
+                commentId: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description No Content */
+            204: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content?: never;
+            };
+        };
+    };
+    editComment: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                documentId: string;
+                commentId: string;
+            };
+            cookie?: never;
+        };
+        requestBody: {
+            content: {
+                "application/json": components["schemas"]["CreateCommentDTO"];
+            };
+        };
+        responses: {
+            /** @description OK */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "*/*": components["schemas"]["DocumentComment"];
+                };
+            };
+        };
+    };
     searchTags: {
         parameters: {
             query?: {
@@ -1422,4 +1839,25 @@ export interface operations {
             };
         };
     };
+    deleteAnnotation: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                documentId: string;
+                annotationId: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description No Content */
+            204: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content?: never;
+            };
+        };
+    };
 }

frontend/src/routes/+page.svelte

@@ -250,16 +250,6 @@ $effect(() => {
 										>
 											{doc.title || doc.originalFilename}
 										</h3>
-
-										<!-- Status Badge -->
-										<span
-											class="ml-3 inline-flex items-center rounded-full border px-2.5 py-0.5 text-[10px] font-bold tracking-wide uppercase
-                                            {doc.status === 'UPLOADED'
-												? 'border-brand-mint/50 bg-brand-mint/20 text-brand-navy'
-												: 'border-yellow-200 bg-yellow-50 text-yellow-700'}"
-										>
-											{doc.status}
-										</span>
 									</div>
 
 									<!-- Metadata Row -->

frontend/src/routes/admin/+page.svelte

@@ -11,6 +11,8 @@ let editingTagName = $state('');
 let editingGroupId: string | null = $state(null);
 let backfillResult: number | null = $state(null);
 let backfillLoading = $state(false);
+let backfillHashesResult: number | null = $state(null);
+let backfillHashesLoading = $state(false);
 
 const availablePermissions = ['WRITE_ALL', 'ADMIN', 'ADMIN_USER', 'ADMIN_TAG', 'ADMIN_PERMISSION'];
 
@@ -45,6 +47,20 @@ async function backfillVersions() {
 		backfillLoading = false;
 	}
 }
+
+async function backfillFileHashes() {
+	backfillHashesLoading = true;
+	backfillHashesResult = null;
+	try {
+		const res = await fetch('/api/admin/backfill-file-hashes', { method: 'POST' });
+		if (res.ok) {
+			const data = await res.json();
+			backfillHashesResult = data.count;
+		}
+	} finally {
+		backfillHashesLoading = false;
+	}
+}
 </script>
 
 <div class="mx-auto max-w-7xl py-8 font-sans sm:px-6 lg:px-8">
@@ -535,5 +551,24 @@ async function backfillVersions() {
 				</p>
 			{/if}
 		</div>
+
+		<div class="mt-4 rounded-sm border border-brand-sand bg-white p-6 shadow-sm">
+			<h2 class="mb-1 text-lg font-bold text-gray-700">
+				{m.admin_system_backfill_hashes_heading()}
+			</h2>
+			<p class="mb-4 text-sm text-gray-500">{m.admin_system_backfill_hashes_description()}</p>
+			<button
+				onclick={backfillFileHashes}
+				disabled={backfillHashesLoading}
+				class="rounded bg-brand-navy px-6 py-2 text-sm font-bold text-white uppercase transition hover:bg-brand-mint hover:text-brand-navy disabled:cursor-not-allowed disabled:opacity-50"
+			>
+				{backfillHashesLoading ? '…' : m.admin_system_backfill_hashes_btn()}
+			</button>
+			{#if backfillHashesResult !== null}
+				<p class="mt-4 text-sm font-medium text-brand-navy">
+					{m.admin_system_backfill_hashes_success({ count: backfillHashesResult })}
+				</p>
+			{/if}
+		</div>
 	{/if}
 </div>

frontend/src/routes/documents/[id]/+page.svelte

@@ -1,10 +1,10 @@
 <script lang="ts">
-import { onMount } from 'svelte';
-import DocumentTopBar from '$lib/components/DocumentTopBar.svelte';
-import DocumentViewer from '$lib/components/DocumentViewer.svelte';
-import DocumentBottomPanel from '$lib/components/DocumentBottomPanel.svelte';
-
-type Tab = 'metadata' | 'transcription' | 'discussion' | 'history';
+import { m } from '$lib/paraglide/messages.js';
+import { formatDate } from '$lib/utils/date';
+import { diffWords } from 'diff';
+import ExpandableText from '$lib/components/ExpandableText.svelte';
+import PdfViewer from '$lib/components/PdfViewer.svelte';
+import CommentThread from '$lib/components/CommentThread.svelte';
 
 let { data } = $props();
 
@@ -17,11 +17,9 @@ const canAdmin = $derived(
 );
 const currentUserId = $derived((data.user?.id as string | undefined) ?? null);
 
-// ── File loading ──────────────────────────────────────────────────────────────
-
 let fileUrl = $state('');
 let isLoading = $state(false);
-let fileError = $state('');
+let error = $state('');
 
 $effect(() => {
 	if (doc?.id && doc?.filePath) {
@@ -31,7 +29,7 @@ $effect(() => {
 
 async function loadFile(id: string) {
 	isLoading = true;
-	fileError = '';
+	error = '';
 	fileUrl = '';
 
 	try {
@@ -46,104 +44,873 @@ async function loadFile(id: string) {
 		fileUrl = URL.createObjectURL(blob);
 	} catch (e) {
 		console.error(e);
-		fileError = 'Vorschau konnte nicht geladen werden.';
+		error = m.doc_file_error_preview();
 	} finally {
 		isLoading = false;
 	}
 }
 
-// ── Annotation state (lifted from PdfViewer) ──────────────────────────────────
+// ── History panel ────────────────────────────────────────────────────────────
 
-let annotateMode = $state(false);
-let activeAnnotationId = $state<string | null>(null);
+type VersionSummary = {
+	id: string;
+	savedAt: string;
+	editorName: string;
+	changedFields: string[];
+};
 
-// When an annotation is clicked, open the Diskussion tab.
-$effect(() => {
-	if (activeAnnotationId) {
-		activeTab = 'discussion';
-		panelOpen = true;
+type SnapshotDoc = {
+	title?: string;
+	documentDate?: string;
+	location?: string;
+	documentLocation?: string;
+	transcription?: string;
+	summary?: string;
+	sender?: { id: string; firstName: string; lastName: string } | null;
+	receivers?: { id: string; firstName: string; lastName: string }[];
+	tags?: { id: string; name: string }[];
+};
+
+type DiffEntry =
+	| {
+			kind: 'text';
+			field: string;
+			label: string;
+			parts: { value: string; added?: boolean; removed?: boolean }[];
+	  }
+	| { kind: 'scalar'; field: string; label: string; oldVal: string; newVal: string }
+	| { kind: 'relation'; field: string; label: string; removed: string[]; added: string[] };
+
+let historyOpen = $state(false);
+let historyLoaded = $state(false);
+let historyLoading = $state(false);
+let versions = $state<VersionSummary[]>([]);
+
+let compareMode = $state(false);
+let compareA = $state('');
+let compareB = $state('');
+
+let selectedVersionId = $state<string | null>(null);
+let diffEntries = $state<DiffEntry[]>([]);
+let diffLoading = $state(false);
+let noDiff = $state(false);
+
+const fieldLabels: Record<string, () => string> = {
+	title: m.history_field_title,
+	documentDate: m.history_field_document_date,
+	location: m.history_field_location,
+	documentLocation: m.history_field_document_location,
+	transcription: m.history_field_transcription,
+	summary: m.history_field_summary,
+	sender: m.history_field_sender,
+	receivers: m.history_field_receivers,
+	tags: m.history_field_tags
+};
+
+const TEXT_FIELDS = ['title', 'summary', 'transcription'] as const;
+const SCALAR_FIELDS = ['documentDate', 'location', 'documentLocation'] as const;
+
+function parseSnapshot(raw: string): SnapshotDoc {
+	try {
+		return JSON.parse(raw) as SnapshotDoc;
+	} catch {
+		return {};
 	}
-});
+}
 
-// ── Bottom panel state ────────────────────────────────────────────────────────
+function personLabel(p: { firstName: string; lastName: string }): string {
+	return `${p.firstName} ${p.lastName}`.trim();
+}
 
-const LS_KEY_OPEN = 'doc-panel-open';
-const LS_KEY_HEIGHT = 'doc-panel-height';
-const LS_KEY_TAB = 'doc-panel-tab';
+const DIFF_CONTEXT_WORDS = 4;
 
-let panelOpen = $state(false);
-let panelHeight = $state(320);
-let activeTab = $state<Tab>('metadata');
-let localStorageRestored = $state(false);
+type DiffPart = { value: string; added?: boolean; removed?: boolean };
 
-onMount(() => {
-	const savedOpen = localStorage.getItem(LS_KEY_OPEN);
-	const savedHeight = localStorage.getItem(LS_KEY_HEIGHT);
-	const savedTab = localStorage.getItem(LS_KEY_TAB);
+function trimContextParts(parts: DiffPart[]): DiffPart[] {
+	return parts.flatMap((part, i) => {
+		if (part.added || part.removed) return [part];
+		const tokens = part.value.split(/(\s+)/).filter(Boolean);
+		const wordCount = tokens.filter((t) => /\S/.test(t)).length;
+		if (wordCount <= DIFF_CONTEXT_WORDS * 2) return [part];
 
-	if (savedTab && ['metadata', 'transcription', 'discussion', 'history'].includes(savedTab)) {
-		activeTab = savedTab as Tab;
-	}
-	if (savedHeight) {
-		const h = parseInt(savedHeight, 10);
-		if (!isNaN(h) && h >= 80) panelHeight = h;
-	}
-	if (savedOpen !== null) {
-		panelOpen = savedOpen === 'true';
-	} else if (!doc.filePath) {
-		// No previous state and no file → open to Metadaten by default
-		panelOpen = true;
-		activeTab = 'metadata';
+		function keepFirst(n: number): string {
+			let count = 0;
+			const out: string[] = [];
+			for (const t of tokens) {
+				out.push(t);
+				if (/\S/.test(t) && ++count >= n) break;
+			}
+			return out.join('');
+		}
+		function keepLast(n: number): string {
+			let count = 0;
+			const out: string[] = [];
+			for (const t of [...tokens].reverse()) {
+				out.unshift(t);
+				if (/\S/.test(t) && ++count >= n) break;
+			}
+			return out.join('');
+		}
+
+		const isFirst = i === 0;
+		const isLast = i === parts.length - 1;
+		if (isFirst) return [{ value: '… ' + keepLast(DIFF_CONTEXT_WORDS) }];
+		if (isLast) return [{ value: keepFirst(DIFF_CONTEXT_WORDS) + ' …' }];
+		return [{ value: keepFirst(DIFF_CONTEXT_WORDS) + ' … ' + keepLast(DIFF_CONTEXT_WORDS) }];
+	});
+}
+
+function buildDiff(older: SnapshotDoc | null, newer: SnapshotDoc): DiffEntry[] {
+	const entries: DiffEntry[] = [];
+
+	for (const field of TEXT_FIELDS) {
+		const a = older?.[field] ?? '';
+		const b = newer[field] ?? '';
+		if (a === b) continue;
+		const parts = trimContextParts(diffWords(a, b));
+		entries.push({ kind: 'text', field, label: fieldLabels[field](), parts });
 	}
 
-	localStorageRestored = true;
-});
+	for (const field of SCALAR_FIELDS) {
+		const a = older?.[field] ?? '';
+		const b = newer[field] ?? '';
+		if (a === b) continue;
+		entries.push({ kind: 'scalar', field, label: fieldLabels[field](), oldVal: a, newVal: b });
+	}
 
-// Persist panel state whenever it changes (after initial restore).
-$effect(() => {
-	if (!localStorageRestored) return;
-	localStorage.setItem(LS_KEY_OPEN, String(panelOpen));
-	localStorage.setItem(LS_KEY_HEIGHT, String(panelHeight));
-	localStorage.setItem(LS_KEY_TAB, activeTab);
-});
+	// sender
+	const senderA = older?.sender ? personLabel(older.sender) : '';
+	const senderB = newer.sender ? personLabel(newer.sender) : '';
+	if (senderA !== senderB) {
+		const removed = senderA ? [senderA] : [];
+		const added = senderB ? [senderB] : [];
+		entries.push({
+			kind: 'relation',
+			field: 'sender',
+			label: fieldLabels['sender'](),
+			removed,
+			added
+		});
+	}
+
+	// receivers
+	const receiversA = new Set((older?.receivers ?? []).map(personLabel));
+	const receiversB = new Set((newer.receivers ?? []).map(personLabel));
+	const removedReceivers = [...receiversA].filter((r) => !receiversB.has(r));
+	const addedReceivers = [...receiversB].filter((r) => !receiversA.has(r));
+	if (removedReceivers.length > 0 || addedReceivers.length > 0) {
+		entries.push({
+			kind: 'relation',
+			field: 'receivers',
+			label: fieldLabels['receivers'](),
+			removed: removedReceivers,
+			added: addedReceivers
+		});
+	}
+
+	// tags
+	const tagsA = new Set((older?.tags ?? []).map((t) => t.name));
+	const tagsB = new Set((newer.tags ?? []).map((t) => t.name));
+	const removedTags = [...tagsA].filter((t) => !tagsB.has(t));
+	const addedTags = [...tagsB].filter((t) => !tagsA.has(t));
+	if (removedTags.length > 0 || addedTags.length > 0) {
+		entries.push({
+			kind: 'relation',
+			field: 'tags',
+			label: fieldLabels['tags'](),
+			removed: removedTags,
+			added: addedTags
+		});
+	}
+
+	return entries;
+}
+
+async function fetchSnapshot(versionId: string): Promise<SnapshotDoc> {
+	const res = await fetch(`/api/documents/${doc.id}/versions/${versionId}`);
+	if (!res.ok) throw new Error('Failed to fetch version');
+	const v = await res.json();
+	return parseSnapshot(v.snapshot);
+}
+
+async function toggleHistory() {
+	historyOpen = !historyOpen;
+	if (historyOpen && !historyLoaded) {
+		historyLoading = true;
+		try {
+			const res = await fetch(`/api/documents/${doc.id}/versions`);
+			if (res.ok) {
+				versions = await res.json();
+			}
+			historyLoaded = true;
+		} catch {
+			// ignore
+		} finally {
+			historyLoading = false;
+		}
+	}
+}
+
+async function selectVersion(versionId: string) {
+	if (selectedVersionId === versionId) {
+		selectedVersionId = null;
+		diffEntries = [];
+		noDiff = false;
+		return;
+	}
+	selectedVersionId = versionId;
+	diffEntries = [];
+	noDiff = false;
+	diffLoading = true;
+	try {
+		const idx = versions.findIndex((v) => v.id === versionId);
+		const newerSnap = await fetchSnapshot(versionId);
+		const olderSnap = idx > 0 ? await fetchSnapshot(versions[idx - 1].id) : null;
+		const entries = buildDiff(olderSnap, newerSnap);
+		if (entries.length === 0) {
+			noDiff = true;
+		} else {
+			diffEntries = entries;
+		}
+	} catch {
+		// ignore
+	} finally {
+		diffLoading = false;
+	}
+}
+
+async function applyCompare() {
+	if (!compareA || !compareB || compareA === compareB) return;
+	selectedVersionId = null;
+	diffEntries = [];
+	noDiff = false;
+	diffLoading = true;
+	try {
+		const [snapA, snapB] = await Promise.all([fetchSnapshot(compareA), fetchSnapshot(compareB)]);
+		// compareA is the "older" baseline, compareB is "newer"
+		const entries = buildDiff(snapA, snapB);
+		if (entries.length === 0) {
+			noDiff = true;
+		} else {
+			diffEntries = entries;
+		}
+	} catch {
+		// ignore
+	} finally {
+		diffLoading = false;
+	}
+}
+
+function formatDateTime(iso: string): string {
+	try {
+		return new Intl.DateTimeFormat('de-DE', {
+			day: 'numeric',
+			month: 'short',
+			year: 'numeric',
+			hour: '2-digit',
+			minute: '2-digit'
+		}).format(new Date(iso));
+	} catch {
+		return iso;
+	}
+}
+
+function versionLabel(v: VersionSummary, index: number): string {
+	return `Version ${index + 1} — ${v.editorName} — ${formatDateTime(v.savedAt)}`;
+}
 </script>
 
-<svelte:head>
-	<title>{doc.title || doc.originalFilename || 'Dokument'}</title>
-</svelte:head>
+<div class="flex h-screen flex-col bg-white">
+	<!-- Top Bar -->
+	<div
+		class="z-10 flex items-center justify-between border-b border-brand-sand bg-white px-6 py-4 shadow-sm"
+	>
+		<div class="flex items-center gap-6 overflow-hidden">
+			<a
+				href="/"
+				class="group flex flex-shrink-0 items-center gap-2 font-sans text-sm font-medium text-gray-500 transition-colors hover:text-brand-navy"
+			>
+				<div
+					class="flex h-8 w-8 items-center justify-center rounded-full bg-brand-sand transition-colors group-hover:bg-brand-mint"
+				>
+					<img
+						src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Arrow/Arrow-Left-MD.svg"
+						alt=""
+						aria-hidden="true"
+						class="h-4 w-4"
+					/>
+				</div>
+				<span>{m.btn_back()}</span>
+			</a>
 
-<div class="flex h-screen flex-col overflow-hidden bg-white" data-hydrated>
-	<DocumentTopBar
-		doc={doc}
-		canWrite={data.canWrite ?? false}
-		canAnnotate={data.canAnnotate ?? false}
-		fileUrl={fileUrl}
-		bind:annotateMode={annotateMode}
-	/>
+			<div class="flex items-center gap-4 overflow-hidden border-l border-gray-200 pl-6">
+				<h1 class="truncate font-serif text-xl text-brand-navy" title={doc.title}>
+					{doc.title || doc.originalFilename}
+				</h1>
+			</div>
+		</div>
 
-	<div class="relative flex-1 overflow-hidden">
-		<DocumentViewer
-			doc={doc}
-			fileUrl={fileUrl}
-			isLoading={isLoading}
-			error={fileError}
-			bind:annotateMode={annotateMode}
-			bind:activeAnnotationId={activeAnnotationId}
-			onAnnotationClick={(id) => {
-				activeAnnotationId = id;
-			}}
-		/>
+		<div class="ml-4 flex flex-shrink-0 items-center gap-3 font-sans">
+			{#if data.canWrite}
+				<a
+					href="/documents/{doc.id}/edit"
+					class="flex items-center gap-2 rounded border border-brand-navy bg-transparent px-4 py-2 text-sm font-medium text-brand-navy transition hover:bg-brand-navy hover:text-white"
+				>
+					<img
+						src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Edit-Content-MD.svg"
+						alt=""
+						aria-hidden="true"
+						class="h-4 w-4"
+					/>
+					{m.btn_edit()}
+				</a>
+			{/if}
+
+			{#if doc.filePath}
+				<a
+					href={fileUrl}
+					download={doc.originalFilename}
+					class="rounded border border-transparent bg-brand-sand/50 p-2 text-brand-navy transition hover:bg-brand-mint"
+					title={m.doc_download_title()}
+				>
+					<img
+						src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Download-MD.svg"
+						alt=""
+						aria-hidden="true"
+						class="h-5 w-5"
+					/>
+				</a>
+			{/if}
+		</div>
+	</div>
+
+	<!-- Content Area -->
+	<div class="flex flex-1 overflow-hidden">
+		<!-- LEFT SIDEBAR: METADATA -->
+		<aside
+			class="custom-scrollbar w-96 flex-shrink-0 overflow-y-auto border-r border-brand-sand bg-white p-8"
+		>
+			<div class="space-y-10">
+				<!-- 1. DETAILS GROUP -->
+				<div>
+					<h3
+						class="mb-4 border-b border-brand-sand pb-2 font-sans text-xs font-bold tracking-widest text-brand-navy uppercase"
+					>
+						{m.doc_section_details()}
+					</h3>
+					<div class="space-y-5">
+						<!-- Date -->
+						<div class="group flex items-start">
+							<span class="mt-0.5 w-8 text-brand-mint">
+								<img
+									src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Calendar/Calendar-Add-MD.svg"
+									alt=""
+									aria-hidden="true"
+									class="h-5 w-5"
+								/>
+							</span>
+							<div>
+								<span class="block font-serif text-lg text-brand-navy">
+									{doc.documentDate ? formatDate(doc.documentDate) : '—'}
+								</span>
+								<span class="font-sans text-xs text-gray-500">{m.doc_label_document_date()}</span>
+							</div>
+						</div>
+
+						<!-- Creation Location -->
+						<div class="group flex items-start">
+							<span class="mt-0.5 w-8 text-brand-mint">
+								<img
+									src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Location-MD.svg"
+									alt=""
+									aria-hidden="true"
+									class="h-5 w-5"
+								/>
+							</span>
+							<div>
+								<span class="block font-serif text-lg text-brand-navy">
+									{doc.location ? doc.location : '—'}
+								</span>
+								<span class="font-sans text-xs text-gray-500"
+									>{m.doc_label_creation_location()}</span
+								>
+							</div>
+						</div>
+
+						<!-- Physical Archive Location -->
+						{#if doc.documentLocation}
+							<div class="group flex items-start">
+								<span class="mt-0.5 w-8 text-brand-mint">
+									<img
+										src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Folder-MD.svg"
+										alt=""
+										aria-hidden="true"
+										class="h-5 w-5"
+									/>
+								</span>
+								<div>
+									<span class="block font-serif text-lg text-brand-navy">
+										{doc.documentLocation}
+									</span>
+									<span class="font-sans text-xs text-gray-500"
+										>{m.doc_label_archive_location_original()}</span
+									>
+								</div>
+							</div>
+						{/if}
+
+						<!-- TAGS / SCHLAGWORTE -->
+						{#if doc.tags && doc.tags.length > 0}
+							<div class="group flex items-start">
+								<span class="mt-0.5 w-8 text-brand-mint">
+									<img
+										src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Bookmark/Bookmark-Outline-MD.svg"
+										alt=""
+										aria-hidden="true"
+										class="h-5 w-5"
+									/>
+								</span>
+								<div class="flex-1">
+									<div class="mb-1 flex flex-wrap gap-2">
+										{#each doc.tags as tag (tag.id)}
+											<a
+												href="/?tag={encodeURIComponent(tag.name)}"
+												class="inline-flex items-center rounded bg-brand-sand/50 px-2 py-0.5 text-xs font-bold tracking-wide text-brand-navy uppercase transition-colors hover:bg-brand-navy hover:text-white"
+												title={m.doc_tag_filter_title({ name: tag.name })}
+											>
+												{tag.name}
+											</a>
+										{/each}
+									</div>
+									<span class="font-sans text-xs text-gray-500">{m.form_label_tags()}</span>
+								</div>
+							</div>
+						{/if}
+					</div>
+				</div>
+
+				<!-- 2. PERSONEN GROUP -->
+				<div>
+					<h3
+						class="mb-4 border-b border-brand-sand pb-2 font-sans text-xs font-bold tracking-widest text-brand-navy uppercase"
+					>
+						{m.doc_section_persons()}
+					</h3>
+
+					<div class="mb-6">
+						<span class="mb-2 block font-sans text-xs text-gray-400 uppercase"
+							>{m.form_label_sender()}</span
+						>
+						{#if doc.sender}
+							<a
+								href="/persons/{doc.sender.id}"
+								class="group block rounded border border-brand-sand bg-brand-sand/20 p-3 transition hover:border-brand-mint hover:bg-brand-mint/10"
+							>
+								<div class="flex items-center gap-3">
+									<div
+										class="flex h-8 w-8 items-center justify-center rounded-full bg-brand-navy font-serif text-sm text-white"
+									>
+										{doc.sender.firstName[0]}{doc.sender.lastName[0]}
+									</div>
+									<div>
+										<p
+											class="font-serif text-brand-navy decoration-brand-mint underline-offset-2 group-hover:underline"
+										>
+											{doc.sender.firstName}
+											{doc.sender.lastName}
+										</p>
+										{#if doc.sender.alias}
+											<p class="font-sans text-xs text-gray-500">{doc.sender.alias}</p>
+										{/if}
+									</div>
+								</div>
+							</a>
+						{:else}
+							<span class="font-serif text-sm text-gray-400 italic"
+								>{m.doc_sender_not_specified()}</span
+							>
+						{/if}
+					</div>
+
+					<div>
+						<span class="mb-2 block font-sans text-xs text-gray-400 uppercase"
+							>{m.form_label_receivers()}</span
+						>
+						{#if doc.receivers && doc.receivers.length > 0}
+							<div class="space-y-2">
+								{#each doc.receivers as receiver (receiver.id)}
+									<div
+										class="group flex items-center justify-between rounded border border-brand-sand bg-white p-3 transition hover:border-brand-navy"
+									>
+										<a href="/persons/{receiver.id}" class="flex min-w-0 flex-1 items-center gap-3">
+											<div
+												class="flex h-6 w-6 items-center justify-center rounded-full bg-gray-100 font-serif text-xs text-gray-500"
+											>
+												{receiver.firstName[0]}{receiver.lastName[0]}
+											</div>
+											<span
+												class="truncate font-serif text-sm text-brand-navy group-hover:text-brand-navy"
+											>
+												{receiver.firstName}
+												{receiver.lastName}
+											</span>
+										</a>
+
+										{#if doc.sender}
+											<a
+												href="/conversations?senderId={doc.sender.id}&receiverId={receiver.id}"
+												class="text-gray-300 transition hover:text-brand-mint"
+												title={m.doc_conversation_title()}
+											>
+												<img
+													src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Chat-MD.svg"
+													alt=""
+													aria-hidden="true"
+													class="h-5 w-5"
+												/>
+											</a>
+										{/if}
+									</div>
+								{/each}
+							</div>
+						{:else}
+							<span class="font-serif text-sm text-gray-400 italic">{m.doc_no_receivers()}</span>
+						{/if}
+					</div>
+				</div>
+
+				<!-- 3. INHALT GROUP -->
+				{#if doc.summary || doc.transcription}
+					<div>
+						<h3
+							class="mb-4 border-b border-brand-sand pb-2 font-sans text-xs font-bold tracking-widest text-brand-navy uppercase"
+						>
+							{m.doc_section_content()}
+						</h3>
+
+						<div class="space-y-6">
+							{#if doc.summary}
+								<div>
+									<span class="mb-2 block font-sans text-xs text-gray-400 uppercase"
+										>{m.doc_label_summary()}</span
+									>
+									<ExpandableText text={doc.summary} />
+								</div>
+							{/if}
+
+							{#if doc.transcription}
+								<div>
+									<span class="mb-2 block font-sans text-xs text-gray-400 uppercase"
+										>{m.form_label_transcription()}</span
+									>
+									<ExpandableText text={doc.transcription} />
+								</div>
+							{/if}
+						</div>
+					</div>
+				{/if}
+
+				<!-- 4. HISTORY GROUP -->
+				<div>
+					<div class="flex items-center justify-between border-b border-brand-sand pb-2">
+						<h3 class="font-sans text-xs font-bold tracking-widest text-brand-navy uppercase">
+							{m.history_section_title()}
+						</h3>
+						<button
+							onclick={toggleHistory}
+							class="flex items-center gap-1 rounded p-1 text-gray-400 transition hover:bg-brand-sand/50 hover:text-brand-navy"
+							aria-expanded={historyOpen}
+							aria-label={m.history_section_title()}
+						>
+							<svg
+								class="h-4 w-4 transition-transform duration-200 {historyOpen ? 'rotate-180' : ''}"
+								viewBox="0 0 20 20"
+								fill="currentColor"
+								aria-hidden="true"
+							>
+								<path
+									fill-rule="evenodd"
+									d="M5.293 7.293a1 1 0 011.414 0L10 10.586l3.293-3.293a1 1 0 111.414 1.414l-4 4a1 1 0 01-1.414 0l-4-4a1 1 0 010-1.414z"
+									clip-rule="evenodd"
+								/>
+							</svg>
+						</button>
+					</div>
+
+					{#if historyOpen}
+						<div class="mt-4 space-y-3">
+							{#if historyLoading}
+								<p class="font-sans text-xs text-gray-400">{m.history_loading()}</p>
+							{:else if versions.length === 0}
+								<p class="font-serif text-sm text-gray-400 italic">{m.history_empty()}</p>
+							{:else}
+								<!-- Compare mode toggle -->
+								<div class="flex justify-end">
+									<button
+										onclick={() => {
+											compareMode = !compareMode;
+											diffEntries = [];
+											noDiff = false;
+											selectedVersionId = null;
+										}}
+										class="font-sans text-xs font-medium transition {compareMode
+											? 'text-brand-navy underline'
+											: 'text-gray-400 hover:text-brand-navy'}"
+									>
+										{m.history_compare_mode()}
+									</button>
+								</div>
+
+								{#if compareMode}
+									<!-- Compare selects -->
+									<div class="space-y-2">
+										<div>
+											<label
+												for="compare-a"
+												class="mb-1 block font-sans text-[10px] text-gray-400 uppercase"
+												>{m.history_compare_select_a()}</label
+											>
+											<select
+												id="compare-a"
+												bind:value={compareA}
+												class="w-full rounded border border-brand-sand bg-white px-2 py-1 font-sans text-xs text-brand-navy focus:ring-1 focus:ring-brand-mint focus:outline-none"
+											>
+												<option value="">—</option>
+												{#each versions as v, i (v.id)}
+													<option value={v.id}>{versionLabel(v, i)}</option>
+												{/each}
+											</select>
+										</div>
+										<div>
+											<label
+												for="compare-b"
+												class="mb-1 block font-sans text-[10px] text-gray-400 uppercase"
+												>{m.history_compare_select_b()}</label
+											>
+											<select
+												id="compare-b"
+												bind:value={compareB}
+												class="w-full rounded border border-brand-sand bg-white px-2 py-1 font-sans text-xs text-brand-navy focus:ring-1 focus:ring-brand-mint focus:outline-none"
+											>
+												<option value="">—</option>
+												{#each versions as v, i (v.id)}
+													<option value={v.id}>{versionLabel(v, i)}</option>
+												{/each}
+											</select>
+										</div>
+										<button
+											onclick={applyCompare}
+											disabled={!compareA || !compareB || compareA === compareB}
+											class="w-full rounded bg-brand-navy px-3 py-1.5 font-sans text-xs font-medium text-white transition hover:bg-brand-navy/80 disabled:cursor-not-allowed disabled:opacity-40"
+										>
+											{m.history_compare_apply()}
+										</button>
+									</div>
+								{:else}
+									<!-- Version list -->
+									<ul class="divide-y divide-brand-sand">
+										{#each versions as v, i (v.id)}
+											<li>
+												<button
+													onclick={() => selectVersion(v.id)}
+													data-testid="history-version"
+													class="w-full py-2 text-left transition hover:bg-brand-sand/30 {selectedVersionId ===
+													v.id
+														? 'border-l-2 border-brand-mint pl-2'
+														: 'pl-0'}"
+												>
+													<div class="flex items-baseline justify-between gap-2">
+														<span class="font-sans text-xs font-medium text-brand-navy">
+															Version {i + 1}
+														</span>
+														<span class="font-sans text-[10px] text-gray-400">
+															{formatDateTime(v.savedAt)}
+														</span>
+													</div>
+													<span class="font-sans text-[11px] text-gray-500">{v.editorName}</span>
+													{#if v.changedFields && v.changedFields.length > 0}
+														<div class="mt-1 flex flex-wrap gap-1">
+															{#each v.changedFields as field (field)}
+																<span
+																	class="rounded bg-brand-sand/50 px-1.5 py-0.5 font-sans text-[10px] tracking-wide text-gray-500 uppercase"
+																>
+																	{fieldLabels[field] ? fieldLabels[field]() : field}
+																</span>
+															{/each}
+														</div>
+													{/if}
+												</button>
+											</li>
+										{/each}
+									</ul>
+								{/if}
+
+								<!-- Diff panel -->
+								{#if diffLoading}
+									<p class="font-sans text-xs text-gray-400">{m.history_loading()}</p>
+								{:else if noDiff}
+									<div
+										data-testid="history-diff"
+										class="rounded-sm border border-brand-sand bg-white p-4 font-serif text-sm text-gray-400 italic"
+									>
+										{m.history_diff_no_changes()}
+									</div>
+								{:else if diffEntries.length > 0}
+									<div
+										data-testid="history-diff"
+										class="space-y-4 rounded-sm border border-brand-sand bg-white p-4"
+									>
+										{#each diffEntries as entry (entry.field)}
+											<div>
+												<span
+													class="mb-1.5 block font-sans text-[10px] font-bold tracking-wide text-gray-400 uppercase"
+													>{entry.label}</span
+												>
+												{#if entry.kind === 'text'}
+													<p class="font-serif text-sm leading-relaxed">
+														{#each entry.parts as part, partIdx (partIdx)}
+															{#if part.added}
+																<span class="bg-green-50 text-green-700">{part.value}</span>
+															{:else if part.removed}
+																<span class="bg-red-50 text-red-600 line-through">{part.value}</span
+																>
+															{:else}
+																<span>{part.value}</span>
+															{/if}
+														{/each}
+													</p>
+												{:else if entry.kind === 'scalar'}
+													<div class="flex items-center gap-2 font-serif text-sm">
+														<span class="text-red-600 line-through">{entry.oldVal || '—'}</span>
+														<svg
+															class="h-3 w-3 flex-shrink-0 text-gray-400"
+															viewBox="0 0 20 20"
+															fill="currentColor"
+															aria-hidden="true"
+														>
+															<path
+																fill-rule="evenodd"
+																d="M10.293 3.293a1 1 0 011.414 0l6 6a1 1 0 010 1.414l-6 6a1 1 0 01-1.414-1.414L14.586 11H3a1 1 0 110-2h11.586l-4.293-4.293a1 1 0 010-1.414z"
+																clip-rule="evenodd"
+															/>
+														</svg>
+														<span class="text-green-700">{entry.newVal || '—'}</span>
+													</div>
+												{:else if entry.kind === 'relation'}
+													<div class="flex flex-wrap gap-1.5">
+														{#each entry.removed as item (item)}
+															<span
+																class="rounded bg-red-50 px-1.5 py-0.5 font-sans text-[11px] text-red-600 line-through"
+																>{item}</span
+															>
+														{/each}
+														{#each entry.added as item (item)}
+															<span
+																class="rounded bg-green-50 px-1.5 py-0.5 font-sans text-[11px] text-green-700"
+																>{item}</span
+															>
+														{/each}
+													</div>
+												{/if}
+											</div>
+										{/each}
+									</div>
+								{/if}
+							{/if}
+						</div>
+					{/if}
+				</div>
+
+				<!-- 5. DISKUSSION -->
+				<div>
+					<div class="border-b border-brand-sand pb-2">
+						<h3 class="font-sans text-xs font-bold tracking-widest text-brand-navy uppercase">
+							{m.comment_section_title()}
+						</h3>
+					</div>
+					<div class="mt-4">
+						<CommentThread
+							documentId={doc.id}
+							initialComments={data.comments ?? []}
+							canComment={canComment}
+							currentUserId={currentUserId}
+							canAdmin={canAdmin}
+						/>
+					</div>
+				</div>
+
+				<!-- Footer -->
+				<div class="border-t border-brand-sand pt-4 font-sans text-[10px] text-gray-400">
+					<p class="truncate">ID: {doc.id}</p>
+					<p class="mt-1 truncate">{doc.originalFilename}</p>
+				</div>
+			</div>
+		</aside>
+
+		<!-- RIGHT: PREVIEW AREA -->
+		<main class="relative flex flex-1 flex-col items-center justify-center bg-[#2A2A2A]">
+			{#if isLoading}
+				<div class="flex flex-col items-center text-brand-mint">
+					<svg
+						class="mb-4 h-8 w-8 animate-spin"
+						xmlns="http://www.w3.org/2000/svg"
+						fill="none"
+						viewBox="0 0 24 24"
+					>
+						<circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"
+						></circle>
+						<path
+							class="opacity-75"
+							fill="currentColor"
+							d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"
+						></path>
+					</svg>
+					<span class="font-sans text-sm tracking-wide">{m.doc_loading()}</span>
+				</div>
+			{:else if error}
+				<div class="px-4 text-center text-gray-400">
+					<p class="mb-2 font-serif">{error}</p>
+					{#if doc.filePath}
+						<a
+							href={`/api/documents/${doc.id}/file`}
+							target="_blank"
+							class="text-sm underline hover:text-white"
+						>
+							{m.doc_download_link()}
+						</a>
+					{/if}
+				</div>
+			{:else if !doc.filePath}
+				<div class="flex flex-col items-center text-gray-400">
+					<div class="mb-6 rounded-full bg-white/5 p-8">
+						<img
+							src="/degruyter-icons/Simple/Medium-24px/SVG/Action/PDF-Document-MD.svg"
+							alt=""
+							aria-hidden="true"
+							class="h-12 w-12 opacity-50 invert"
+						/>
+					</div>
+					<p class="font-sans text-sm tracking-wide uppercase">{m.doc_no_scan()}</p>
+				</div>
+			{:else if fileUrl && doc.contentType?.startsWith('application/pdf')}
+				<PdfViewer
+					url={fileUrl}
+					documentId={doc.id}
+					canAnnotate={data.canAnnotate}
+					canComment={canComment}
+					currentUserId={currentUserId}
+					canAdmin={canAdmin}
+					documentFileHash={doc.fileHash ?? null}
+				/>
+			{:else if fileUrl}
+				<div class="flex h-full w-full items-center justify-center overflow-auto p-8">
+					<img
+						src={fileUrl}
+						alt={m.doc_image_alt()}
+						class="max-h-full max-w-full object-contain shadow-2xl"
+					/>
+				</div>
+			{/if}
+		</main>
 	</div>
 </div>
-
-<DocumentBottomPanel
-	doc={doc}
-	comments={(data.comments ?? []) as never[]}
-	canComment={canComment}
-	currentUserId={currentUserId}
-	canAdmin={canAdmin}
-	bind:open={panelOpen}
-	bind:height={panelHeight}
-	bind:activeTab={activeTab}
-	activeAnnotationId={activeAnnotationId}
-/>