feat: Support push and merge_group events with use_rest_api

.github/workflows/test.yml

@@ -666,6 +666,51 @@ jobs:
         shell:
           bash
 
+  test-rest-api-push:
+    name: Test changed-files with REST API on push event (no .git)
+    runs-on: ubuntu-latest
+    needs: build
+    if: github.event_name == 'push' && needs.build.outputs.files_changed != 'true'
+    permissions:
+      contents: read
+    steps:
+      # Checkout is only needed to get action.yml on disk for the runner.
+      # We remove .git afterward to prove the action works purely via API.
+      - name: Checkout action definition only
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          path: dir1
+          sparse-checkout: |
+            action.yml
+          sparse-checkout-cone-mode: false
+
+      - name: Remove .git to prove no local git is needed
+        run: rm -rf dir1/.git
+        shell: bash
+
+      - name: Download build assets
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
+        with:
+          name: build-assets
+          path: dir1/dist
+
+      - name: Run changed-files with REST API on push
+        id: changed-files
+        uses: ./dir1
+        with:
+          use_rest_api: true
+
+      - name: Verify output is not empty
+        run: |
+          echo '${{ toJSON(steps.changed-files.outputs) }}'
+          if [ -z "${{ steps.changed-files.outputs.all_changed_files }}" ]; then
+            echo "::warning::No changed files detected (may be expected for some pushes)"
+          else
+            echo "Changed files detected successfully via REST API on push event"
+          fi
+        shell:
+          bash
+
   test-dir-names-nested-folder:
     name: Test changed-files with dir-names in a nested folder
     runs-on: ubuntu-latest