fix: allow WRITE_ALL users to create and delete annotations

@RequirePermission on POST and DELETE annotation endpoints previously
only listed ANNOTATE_ALL. Users with WRITE_ALL (but not ANNOTATE_ALL)
received 403. A user who can write documents should also be able to
annotate them — both permissions now accepted on both methods.

Also updates canAnnotate in +layout.server.ts to match, so the UI
correctly reflects annotation capability for WRITE_ALL users.

Tests: AnnotationControllerTest (+2 RED→GREEN).

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

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

@@ -35,7 +35,7 @@ public class AnnotationController {
 
     @PostMapping
     @ResponseStatus(HttpStatus.CREATED)
-    @RequirePermission(Permission.ANNOTATE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public DocumentAnnotation createAnnotation(
             @PathVariable UUID documentId,
             @RequestBody CreateAnnotationDTO dto,
@@ -47,7 +47,7 @@ public class AnnotationController {
 
     @DeleteMapping("/{annotationId}")
     @ResponseStatus(HttpStatus.NO_CONTENT)
-    @RequirePermission(Permission.ANNOTATE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public void deleteAnnotation(
             @PathVariable UUID documentId,
             @PathVariable UUID annotationId,

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

@@ -81,6 +81,29 @@ class AnnotationControllerTest {
                 .andExpect(status().isForbidden());
     }
 
+    @Test
+    @WithMockUser(authorities = "WRITE_ALL")
+    void createAnnotation_returns201_whenHasWriteAllPermission() throws Exception {
+        UUID docId = UUID.randomUUID();
+        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(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)
+                        .content(ANNOTATION_JSON))
+                .andExpect(status().isCreated());
+    }
+
+    @Test
+    @WithMockUser(authorities = "WRITE_ALL")
+    void deleteAnnotation_returns204_whenHasWriteAllPermission() throws Exception {
+        mockMvc.perform(delete("/api/documents/" + UUID.randomUUID() + "/annotations/" + UUID.randomUUID()))
+                .andExpect(status().isNoContent());
+    }
+
     @Test
     @WithMockUser(authorities = "ANNOTATE_ALL")
     void createAnnotation_returns201_whenHasAnnotatePermission() throws Exception {