feat(document): reject end date without RANGE precision (#678)

Add the second validateDateRange predicate mirroring
chk_meta_date_end_only_for_range, so a direct API client that sets an end
date without RANGE precision gets a clean 400 INVALID_DATE_RANGE instead of
a 500 (AC6). Shares the code with the end-before-start branch.

Also fix updateDocument_preservesStoredPrecision_whenDtoOmitsIt: its stored
fixture (MONTH + end date) is a state the DB CHECK forbids, so the
carried-over-state guard correctly rejects it. Switched to RANGE + end —
the only DB-valid non-null-end combo — preserving the test's intent.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

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

@@ -486,6 +486,12 @@ public class DocumentService {
             throw DomainException.badRequest(ErrorCode.INVALID_DATE_RANGE,
                     "meta_date_end must not be before meta_date");
         }
+        // Mirrors chk_meta_date_end_only_for_range. API-only: the edit form clears the
+        // end field off-RANGE, so this branch closes the same 500 class for direct clients.
+        if (doc.getMetaDateEnd() != null && doc.getMetaDatePrecision() != DatePrecision.RANGE) {
+            throw DomainException.badRequest(ErrorCode.INVALID_DATE_RANGE,
+                    "meta_date_end is only allowed when meta_date_precision is RANGE");
+        }
     }
 
     @Transactional

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

@@ -204,10 +204,12 @@ class DocumentServiceTest {
         // Editing a doc (e.g. fixing a location typo) without touching the precision
         // controls must NOT fabricate a precision. The form omits the three precision
         // fields → they arrive null on the DTO → the stored values must be preserved.
+        // Stored combo is RANGE + end: the only DB-valid way to have a non-null end
+        // (chk_meta_date_end_only_for_range), so the carried-over state passes the guard.
         UUID id = UUID.randomUUID();
         Document doc = Document.builder()
                 .id(id)
-                .metaDatePrecision(DatePrecision.MONTH)
+                .metaDatePrecision(DatePrecision.RANGE)
                 .metaDateEnd(LocalDate.of(1916, 6, 30))
                 .metaDateRaw("Juni 1916")
                 .receivers(new HashSet<>())
@@ -221,7 +223,7 @@ class DocumentServiceTest {
 
         documentService.updateDocument(id, dto, null, null);
 
-        assertThat(doc.getMetaDatePrecision()).isEqualTo(DatePrecision.MONTH);
+        assertThat(doc.getMetaDatePrecision()).isEqualTo(DatePrecision.RANGE);
         assertThat(doc.getMetaDateEnd()).isEqualTo(LocalDate.of(1916, 6, 30));
         assertThat(doc.getMetaDateRaw()).isEqualTo("Juni 1916");
     }
@@ -313,6 +315,26 @@ class DocumentServiceTest {
         verify(documentRepository, atLeastOnce()).save(any());
     }
 
+    @Test
+    void updateDocument_rejectsEndDate_whenPrecisionNotRange() {
+        // AC6: an end date only makes sense for RANGE (mirrors chk_meta_date_end_only_for_range).
+        // API-only — the edit form clears the end field off-RANGE — so close the 500 class here too.
+        UUID id = UUID.randomUUID();
+        Document doc = docForRangeUpdate(id);
+        when(documentRepository.findById(id)).thenReturn(Optional.of(doc));
+
+        DocumentUpdateDTO dto = new DocumentUpdateDTO();
+        dto.setDocumentDate(LocalDate.of(1917, 1, 10));
+        dto.setMetaDatePrecision(DatePrecision.MONTH);
+        dto.setMetaDateEnd(LocalDate.of(1917, 1, 31));
+
+        assertThatThrownBy(() -> documentService.updateDocument(id, dto, null, null))
+                .isInstanceOf(DomainException.class)
+                .extracting(e -> ((DomainException) e).getCode())
+                .isEqualTo(ErrorCode.INVALID_DATE_RANGE);
+        verify(documentRepository, never()).save(any());
+    }
+
     // ─── deleteTagCascading ───────────────────────────────────────────────────
 
     @Test