merge: resolve conflict with origin/main + fix WCAG AA contrast + add API test

- Merge origin/main (resolved conflict in +page.svelte: use res.ok check from main)
- fix(transcription): bump button text from text-brand-navy/60 (3.83:1) to
  text-brand-navy/80 (6.75:1) to pass WCAG AA 4.5:1 for 12px text
- feat(api-tests): add Transcription.http with PUT /review-all entry

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

backend/api_tests/Transcription.http

@@ -0,0 +1,3 @@
+### Mark all blocks as reviewed
+PUT http://localhost:8080/api/documents/{{documentId}}/transcription-blocks/review-all
+Authorization: Basic admin admin123

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

@@ -154,6 +154,13 @@ class AnnotationControllerTest {
                 .andExpect(status().isForbidden());
     }
 
+    @Test
+    @WithMockUser(authorities = "READ_ALL")
+    void deleteAnnotation_returns403_whenUserHasOnlyReadAllPermission() throws Exception {
+        mockMvc.perform(delete("/api/documents/" + UUID.randomUUID() + "/annotations/" + UUID.randomUUID()))
+                .andExpect(status().isForbidden());
+    }
+
     @Test
     @WithMockUser(authorities = "ANNOTATE_ALL")
     void deleteAnnotation_returns204_whenHasAnnotatePermission() throws Exception {