feat(documents): retrofit WRITE_ALL guard on /incomplete-count + /incomplete/next

Closes the CWE-285 gap Nora flagged on issue #296: both endpoints expose
enrichment-queue information that only writers should see. Brings them in
line with the new /incomplete list endpoint and every other write-path
under DocumentController.

Frontend callers (/enrich/[id]/+page.server.ts) already gate on WRITE_ALL
at the route level, so no client-side change is needed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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

@@ -194,6 +194,7 @@ public class DocumentController {
     }
 
     @GetMapping("/incomplete-count")
+    @RequirePermission(Permission.WRITE_ALL)
     public Map<String, Long> getIncompleteCount() {
         return Map.of("count", documentService.getIncompleteCount());
     }
@@ -207,6 +208,7 @@ public class DocumentController {
     }
 
     @GetMapping("/incomplete/next")
+    @RequirePermission(Permission.WRITE_ALL)
     public ResponseEntity<Document> getNextIncomplete(@RequestParam UUID excludeId) {
         return documentService.findNextIncompleteDocument(excludeId)
                 .map(ResponseEntity::ok)

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

@@ -382,7 +382,7 @@ class DocumentControllerTest {
     }
 
     @Test
-    @WithMockUser
+    @WithMockUser(authorities = "WRITE_ALL")
     void getIncompleteCount_returns200_withCount() throws Exception {
         when(documentService.getIncompleteCount()).thenReturn(3L);
 
@@ -391,6 +391,13 @@ class DocumentControllerTest {
                 .andExpect(jsonPath("$.count").value(3));
     }
 
+    @Test
+    @WithMockUser(authorities = "READ_ALL")
+    void getIncompleteCount_returns403_forReaderOnly() throws Exception {
+        mockMvc.perform(get("/api/documents/incomplete-count"))
+                .andExpect(status().isForbidden());
+    }
+
     // ─── GET /api/documents/incomplete ───────────────────────────────────────
 
     @Test
@@ -442,7 +449,7 @@ class DocumentControllerTest {
     }
 
     @Test
-    @WithMockUser
+    @WithMockUser(authorities = "WRITE_ALL")
     void getNextIncomplete_returns200_whenNextExists() throws Exception {
         UUID excludeId = UUID.randomUUID();
         Document next = Document.builder()
@@ -456,7 +463,15 @@ class DocumentControllerTest {
     }
 
     @Test
-    @WithMockUser
+    @WithMockUser(authorities = "READ_ALL")
+    void getNextIncomplete_returns403_forReaderOnly() throws Exception {
+        mockMvc.perform(get("/api/documents/incomplete/next")
+                        .param("excludeId", UUID.randomUUID().toString()))
+                .andExpect(status().isForbidden());
+    }
+
+    @Test
+    @WithMockUser(authorities = "WRITE_ALL")
     void getNextIncomplete_returns204_whenNoneRemain() throws Exception {
         UUID excludeId = UUID.randomUUID();
         when(documentService.findNextIncompleteDocument(excludeId)).thenReturn(Optional.empty());