feat(ci): add all-required sentinel job

Adds a single CI / all-required status check that depends on the test
job. Enables branch protection to require a single status check entry
rather than enumerating individual CI job names.

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

.gitea/workflows/ci.yml

@@ -24,3 +24,17 @@ jobs:
 
       - name: Test
         run: npm test
+
+  all-required:
+    name: all-required
+    needs: [test]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check test result
+        run: |
+          result="${{ needs.test.result }}"
+          if [ "$result" != "success" ]; then
+            echo "Required job test failed (result: $result)"
+            exit 1
+          fi
+          echo "All required jobs passed"