feat(relationship): add generation to PersonNodeDTO + update all sites (#689)

PersonNodeDTO is a positional record. The optional Integer generation
field is inserted between deathYear and familyMember so all four
construction sites stay readable without a builder.

- RelationshipService.getFamilyNetwork → populates with
  person.getGeneration() (the Stammbaum's strict-rank source on the
  frontend).
- RelationshipInferenceService.findAllFor → populates the same way;
  inference UI does not consume it but the field travels along for
  consistency.
- RelationshipControllerTest fixtures pass null.

Refs #689

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

backend/src/main/java/org/raddatz/familienarchiv/person/relationship/RelationshipInferenceService.java

@@ -96,7 +96,8 @@ public class RelationshipInferenceService {
             if (p == null) continue;
             List<RelationToken> path = shortestPaths.get(id);
             PersonNodeDTO node = new PersonNodeDTO(
-                    p.getId(), p.getDisplayName(), p.getBirthYear(), p.getDeathYear(), p.isFamilyMember());
+                    p.getId(), p.getDisplayName(), p.getBirthYear(), p.getDeathYear(),
+                    p.getGeneration(), p.isFamilyMember());
             out.add(new InferredRelationshipWithPersonDTO(node, labelFor(path), path.size()));
         }
         out.sort(Comparator.comparingInt(InferredRelationshipWithPersonDTO::hops)

backend/src/main/java/org/raddatz/familienarchiv/person/relationship/RelationshipService.java

@@ -66,7 +66,8 @@ public class RelationshipService {
         for (Person p : familyMembers) {
             familyIds.add(p.getId());
             nodes.add(new PersonNodeDTO(
-                    p.getId(), p.getDisplayName(), p.getBirthYear(), p.getDeathYear(), true));
+                    p.getId(), p.getDisplayName(), p.getBirthYear(), p.getDeathYear(),
+                    p.getGeneration(), true));
         }
 
         List<PersonRelationship> familyEdges = relationshipRepository.findAllByRelationTypeIn(

backend/src/main/java/org/raddatz/familienarchiv/person/relationship/dto/PersonNodeDTO.java

@@ -10,5 +10,6 @@ public record PersonNodeDTO(
         @Schema(requiredMode = Schema.RequiredMode.REQUIRED) String displayName,
         Integer birthYear,
         Integer deathYear,
+        Integer generation,
         @Schema(requiredMode = Schema.RequiredMode.REQUIRED) boolean familyMember
 ) {}

backend/src/test/java/org/raddatz/familienarchiv/person/relationship/RelationshipControllerTest.java

@@ -93,7 +93,7 @@ class RelationshipControllerTest {
     @Test
     @WithMockUser(username = "testuser", authorities = {"READ_ALL"})
     void getNetwork_returns200_with_NetworkDTO_for_authenticated_user() throws Exception {
-        PersonNodeDTO node = new PersonNodeDTO(PERSON_ID, "Alice Müller", 1900, 1980, true);
+        PersonNodeDTO node = new PersonNodeDTO(PERSON_ID, "Alice Müller", 1900, 1980, null, true);
         RelationshipDTO edge = new RelationshipDTO(
                 UUID.randomUUID(), PERSON_ID, OTHER_ID,
                 "Alice Müller", 1900, 1980,
@@ -111,7 +111,7 @@ class RelationshipControllerTest {
     @Test
     @WithMockUser(username = "testuser", authorities = {"READ_ALL"})
     void getInferredRelationships_returns200_with_list_for_authenticated_user() throws Exception {
-        PersonNodeDTO relative = new PersonNodeDTO(OTHER_ID, "Bob Müller", 1930, null, true);
+        PersonNodeDTO relative = new PersonNodeDTO(OTHER_ID, "Bob Müller", 1930, null, null, true);
         InferredRelationshipWithPersonDTO inferred =
                 new InferredRelationshipWithPersonDTO(relative, "Großvater", 2);
         when(relationshipService.getInferredRelationships(PERSON_ID))

backend/src/test/java/org/raddatz/familienarchiv/person/relationship/RelationshipServiceTest.java

@@ -237,6 +237,22 @@ class RelationshipServiceTest {
         assertThat(result.edges().get(0).relatedPersonId()).isEqualTo(bob.getId());
     }
 
+    @Test
+    void getFamilyNetwork_populates_generation_on_PersonNodeDTO() {
+        Person walter = Person.builder().id(UUID.randomUUID()).lastName("Raddatz")
+                .familyMember(true).generation(2).build();
+        Person clara = Person.builder().id(UUID.randomUUID()).lastName("Raddatz")
+                .familyMember(true).generation(3).build();
+        when(personService.findAllFamilyMembers()).thenReturn(List.of(walter, clara));
+        when(relationshipRepository.findAllByRelationTypeIn(any())).thenReturn(List.of());
+
+        NetworkDTO result = service.getFamilyNetwork();
+
+        assertThat(result.nodes()).hasSize(2);
+        assertThat(result.nodes().stream().map(n -> n.generation()).toList())
+                .containsExactlyInAnyOrder(2, 3);
+    }
+
     // --- helpers ---
 
     private static Person person(String name) {