feat: wire document versioning into DocumentService and DocumentController

DocumentService now calls documentVersionService.recordVersion() after
createDocument and updateDocument. DocumentController exposes two new
read-only endpoints: GET /{id}/versions and GET /{id}/versions/{versionId}.

Refs #38
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

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

@@ -5,13 +5,18 @@ import java.time.LocalDate;
 import java.util.List;
 import java.util.UUID;
 
+
+
 import org.raddatz.familienarchiv.dto.DocumentUpdateDTO;
+import org.raddatz.familienarchiv.dto.DocumentVersionSummary;
 import org.raddatz.familienarchiv.exception.DomainException;
 import org.raddatz.familienarchiv.exception.ErrorCode;
 import org.raddatz.familienarchiv.model.Document;
+import org.raddatz.familienarchiv.model.DocumentVersion;
 import org.raddatz.familienarchiv.security.Permission;
 import org.raddatz.familienarchiv.security.RequirePermission;
 import org.raddatz.familienarchiv.service.DocumentService;
+import org.raddatz.familienarchiv.service.DocumentVersionService;
 import org.raddatz.familienarchiv.service.FileService;
 import org.springframework.data.domain.Sort;
 import org.springframework.http.HttpHeaders;
@@ -39,6 +44,7 @@ import lombok.extern.slf4j.Slf4j;
 public class DocumentController {
 
     private final DocumentService documentService;
+    private final DocumentVersionService documentVersionService;
     private final FileService fileService;
 
     // --- DOWNLOAD ---
@@ -108,6 +114,18 @@ public class DocumentController {
         return ResponseEntity.ok(documentService.searchDocuments(q, from, to, senderId, receiverId, tags));
     }
 
+    // --- VERSIONS ---
+
+    @GetMapping("/{id}/versions")
+    public List<DocumentVersionSummary> getVersions(@PathVariable UUID id) {
+        return documentVersionService.getSummaries(id);
+    }
+
+    @GetMapping("/{id}/versions/{versionId}")
+    public DocumentVersion getVersion(@PathVariable UUID id, @PathVariable UUID versionId) {
+        return documentVersionService.getVersion(id, versionId);
+    }
+
     @GetMapping("/conversation")
     public List<Document> getConversation(
             @RequestParam UUID senderId,

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

@@ -37,6 +37,7 @@ public class DocumentService {
     private final PersonService personService;
     private final FileService fileService;
     private final TagService tagService;
+    private final DocumentVersionService documentVersionService;
 
     /**
      * Lädt eine Datei hoch.
@@ -125,7 +126,9 @@ public class DocumentService {
             doc.setStatus(DocumentStatus.UPLOADED);
         }
 
-        return documentRepository.save(doc);
+        Document finalDoc = documentRepository.save(doc);
+        documentVersionService.recordVersion(finalDoc);
+        return finalDoc;
     }
 
     @Transactional
@@ -178,7 +181,9 @@ public class DocumentService {
             doc.setStatus(DocumentStatus.UPLOADED);
         }
 
-        return documentRepository.save(doc);
+        Document saved = documentRepository.save(doc);
+        documentVersionService.recordVersion(saved);
+        return saved;
     }
 
     public Document updateDocumentTags(UUID docId, List<String> tagNames) {