[CI] Add ci gate job (vllm-project#11634)

Add ci-gate job to make sure all PR merged with ready label.

- vLLM version: v0.23.0
- vLLM main:
vllm-project/vllm@1f486d9

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>

Author: wangxiyuan

.github/workflows/pr_test.yaml

@@ -215,3 +215,42 @@ jobs:
       ref: ${{ github.event.pull_request.head.sha }}
       base_ref: ${{ github.base_ref }}
       test_groups: ${{ needs.lint-and-select-tests.outputs.test_groups }}
+
+  # Summary gate job — use this single, stable name as the required status check
+  # in GitHub branch protection rules instead of tracking individual matrix job names.
+  ci-gate:
+    needs: [lint-and-select-tests, run-selected-tests]
+    if: always()
+    runs-on: linux-amd64-cpu-2-hk
+    steps:
+      - name: Check all required jobs
+        run: |
+          set -euo pipefail
+
+          LINT_RESULT="${{ needs.lint-and-select-tests.result }}"
+          HAS_TESTS="${{ needs.lint-and-select-tests.outputs.has_tests }}"
+          READY_LABELED="${{ contains(github.event.pull_request.labels.*.name, 'ready') }}"
+
+          echo "=== CI Gate Summary ==="
+          echo "lint-and-select-tests: ${LINT_RESULT}"
+          echo "has_tests: ${HAS_TESTS}"
+          echo "ready label: ${READY_LABELED}"
+
+          if [ "${LINT_RESULT}" != "success" ] && [ "${LINT_RESULT}" != "skipped" ]; then
+            echo "::error::lint-and-select-tests did not succeed (result: ${LINT_RESULT})"
+            exit 1
+          fi
+
+          # Only gate on tests when the PR actually runs them
+          if [ "${HAS_TESTS}" = "true" ] && [ "${READY_LABELED}" = "true" ]; then
+            TESTS_RESULT="${{ needs.run-selected-tests.result }}"
+            echo "run-selected-tests (vllm matrix): ${TESTS_RESULT}"
+            if [ "${TESTS_RESULT}" != "success" ]; then
+              echo "::error::run-selected-tests did not succeed (result: ${TESTS_RESULT})"
+              exit 1
+            fi
+          else
+            echo "Skipped test gate (has_tests=${HAS_TESTS}, ready=${READY_LABELED})."
+          fi
+
+          echo "=== CI Gate: PASSED ==="