ci: add Build Summary aggregator job

The matrix prune in this PR (`[11, 17, 21]` → `[17]` on PR) means
the per-version check names (`build (11)`, `build (21)`) don't
report on PR runs. Branch protection requires those names, so PRs
get permanently blocked.

Add a `Build Summary` aggregator that always runs, reflects the
overall matrix result (success/skipped → green; failure → red), and
emits a stable single check name regardless of matrix shape. Branch
protection should require `Build Summary` instead of the per-version
names — same pattern axonflow-enterprise uses with its
`Build Summary` / `Test Summary` aggregators.

Signed-off-by: Saurabh Jain <saurabhjain1592@gmail.com>

Author: saurabhjain1592

.github/workflows/ci.yml

@@ -94,6 +94,26 @@ jobs:
         if: matrix.java-version == 17
         run: mvn jacoco:check -B
 
+  # Aggregator that always reports a single check name regardless of the
+  # matrix shape (PR-time matrix is `[17]`; push/dispatch is `[11, 17, 21]`).
+  # Branch protection requires `Build Summary`, not the per-version names,
+  # so matrix changes don't strand required checks.
+  build-summary:
+    name: Build Summary
+    needs: [build]
+    if: always()
+    runs-on: ubuntu-latest
+    steps:
+      - name: Aggregate build matrix result
+        run: |
+          result="${{ needs.build.result }}"
+          echo "build matrix result: $result"
+          if [ "$result" != "success" ] && [ "$result" != "skipped" ]; then
+            echo "::error::build matrix did not all pass (result: $result)"
+            exit 1
+          fi
+          echo "Build matrix OK"
+
   lint:
     runs-on: ubuntu-latest