feat(transcription): DTOs accept mentionedPersons sidecar with @Valid cascade

CreateTranscriptionBlockDTO and UpdateTranscriptionBlockDTO gain a
List<PersonMention> mentionedPersons field. @Valid is on the field itself,
not just on the controller method, so JSR-303 recurses into the list
elements when the controller boundary calls @Valid on the @RequestBody. The
collection defaults to an empty ArrayList via @Builder.Default; existing
constructor call sites in TranscriptionServiceTest are extended with
List.of() to match the new @AllArgsConstructor signature.

The controller-side @Valid wiring lands in the next commit alongside the
length-201 validation test.

Refs #362

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/src/main/java/org/raddatz/familienarchiv/dto/CreateTranscriptionBlockDTO.java

@@ -1,14 +1,21 @@
 package org.raddatz.familienarchiv.dto;
 
+import jakarta.validation.Valid;
 import jakarta.validation.constraints.Min;
 import jakarta.validation.constraints.Positive;
 import lombok.AllArgsConstructor;
+import lombok.Builder;
 import lombok.Data;
 import lombok.NoArgsConstructor;
+import org.raddatz.familienarchiv.model.PersonMention;
+
+import java.util.ArrayList;
+import java.util.List;
 
 @Data
 @NoArgsConstructor
 @AllArgsConstructor
+@Builder
 public class CreateTranscriptionBlockDTO {
     @Min(0)
     private int pageNumber;
@@ -22,4 +29,8 @@ public class CreateTranscriptionBlockDTO {
     private double height;
     private String text;
     private String label;
+
+    @Valid
+    @Builder.Default
+    private List<PersonMention> mentionedPersons = new ArrayList<>();
 }

backend/src/main/java/org/raddatz/familienarchiv/dto/UpdateTranscriptionBlockDTO.java

@@ -1,13 +1,24 @@
 package org.raddatz.familienarchiv.dto;
 
+import jakarta.validation.Valid;
 import lombok.AllArgsConstructor;
+import lombok.Builder;
 import lombok.Data;
 import lombok.NoArgsConstructor;
+import org.raddatz.familienarchiv.model.PersonMention;
+
+import java.util.ArrayList;
+import java.util.List;
 
 @Data
 @NoArgsConstructor
 @AllArgsConstructor
+@Builder
 public class UpdateTranscriptionBlockDTO {
     private String text;
     private String label;
+
+    @Valid
+    @Builder.Default
+    private List<PersonMention> mentionedPersons = new ArrayList<>();
 }

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

@@ -98,7 +98,7 @@ class TranscriptionServiceTest {
             return b;
         });
 
-        CreateTranscriptionBlockDTO dto = new CreateTranscriptionBlockDTO(1, 0.1, 0.2, 0.3, 0.4, "hello", null);
+        CreateTranscriptionBlockDTO dto = new CreateTranscriptionBlockDTO(1, 0.1, 0.2, 0.3, 0.4, "hello", null, java.util.List.of());
 
         TranscriptionBlock result = transcriptionService.createBlock(docId, dto, userId);
 
@@ -168,7 +168,7 @@ class TranscriptionServiceTest {
         when(documentService.getDocumentById(any())).thenReturn(
                 Document.builder().scriptType(ScriptType.TYPEWRITER).build());
 
-        UpdateTranscriptionBlockDTO dto = new UpdateTranscriptionBlockDTO("new text", null);
+        UpdateTranscriptionBlockDTO dto = new UpdateTranscriptionBlockDTO("new text", null, java.util.List.of());
 
         TranscriptionBlock result = transcriptionService.updateBlock(docId, blockId, dto, userId);
 
@@ -189,7 +189,7 @@ class TranscriptionServiceTest {
         when(documentService.getDocumentById(any())).thenReturn(
                 Document.builder().scriptType(ScriptType.TYPEWRITER).build());
 
-        UpdateTranscriptionBlockDTO dto = new UpdateTranscriptionBlockDTO("text", "Anrede");
+        UpdateTranscriptionBlockDTO dto = new UpdateTranscriptionBlockDTO("text", "Anrede", java.util.List.of());
 
         TranscriptionBlock result = transcriptionService.updateBlock(docId, blockId, dto, UUID.randomUUID());
 
@@ -208,7 +208,7 @@ class TranscriptionServiceTest {
                 Document.builder().scriptType(ScriptType.TYPEWRITER).build());
 
         TranscriptionBlock result = transcriptionService.updateBlock(
-                docId, blockId, new UpdateTranscriptionBlockDTO("new", null), UUID.randomUUID());
+                docId, blockId, new UpdateTranscriptionBlockDTO("new", null, java.util.List.of()), UUID.randomUUID());
 
         assertThat(result.getSource()).isEqualTo(BlockSource.MANUAL);
     }
@@ -226,7 +226,7 @@ class TranscriptionServiceTest {
         when(documentService.getDocumentById(any())).thenReturn(
                 Document.builder().scriptType(ScriptType.HANDWRITING_KURRENT).sender(sender).build());
 
-        transcriptionService.updateBlock(docId, blockId, new UpdateTranscriptionBlockDTO("text", null), UUID.randomUUID());
+        transcriptionService.updateBlock(docId, blockId, new UpdateTranscriptionBlockDTO("text", null, java.util.List.of()), UUID.randomUUID());
 
         verify(senderModelService).checkAndTriggerTraining(senderId);
     }
@@ -242,7 +242,7 @@ class TranscriptionServiceTest {
         when(documentService.getDocumentById(any())).thenReturn(
                 Document.builder().scriptType(ScriptType.HANDWRITING_KURRENT).build());
 
-        transcriptionService.updateBlock(docId, blockId, new UpdateTranscriptionBlockDTO("text", null), UUID.randomUUID());
+        transcriptionService.updateBlock(docId, blockId, new UpdateTranscriptionBlockDTO("text", null, java.util.List.of()), UUID.randomUUID());
 
         verify(senderModelService, never()).checkAndTriggerTraining(any());
     }
@@ -477,7 +477,7 @@ class TranscriptionServiceTest {
                 Document.builder().scriptType(ScriptType.TYPEWRITER).build());
         when(annotationRepository.findById(annotId)).thenReturn(Optional.of(annotation));
 
-        transcriptionService.updateBlock(docId, blockId, new UpdateTranscriptionBlockDTO("new text", null), userId);
+        transcriptionService.updateBlock(docId, blockId, new UpdateTranscriptionBlockDTO("new text", null, java.util.List.of()), userId);
 
         @SuppressWarnings("unchecked")
         ArgumentCaptor<Map<String, Object>> payloadCaptor = ArgumentCaptor.forClass(Map.class);
@@ -502,7 +502,7 @@ class TranscriptionServiceTest {
         when(documentService.getDocumentById(any())).thenReturn(
                 Document.builder().scriptType(ScriptType.TYPEWRITER).build());
 
-        transcriptionService.updateBlock(docId, blockId, new UpdateTranscriptionBlockDTO("same text", null), userId);
+        transcriptionService.updateBlock(docId, blockId, new UpdateTranscriptionBlockDTO("same text", null, java.util.List.of()), userId);
 
         verify(auditService, never()).logAfterCommit(any(), any(), any(), any());
     }