Clean up GCS fork: minimal changeset vs upstream actions/cache

Realign the fork so it diffs from upstream actions/cache only by the GCS
cache backend, instead of carrying unrelated downgrades and deletions.

- Restore package.json/package-lock.json to upstream 5.0.4 deps; the fork
  had downgraded to 4.2.x. Re-add @google-cloud/storage (gcsCache.ts needs it).
- Rebuild dist/ against the restored deps so it bundles the real GCS client
  rather than a stale build against downgraded deps.
- Restore deleted upstream files: 7 workflow YAMLs, .github/CODEOWNERS,
  .licensed.yml. (To be disabled in the fork, not removed.)
- Revert action.yml/restore/save manifests to upstream name/description/
  author; keep only the gcs-bucket/gcs-path-prefix inputs as the fork diff.
- auto-tag.yml: track upstream's highest semver release tag, moving both the
  exact-version tag and the major alias, instead of force-pinning v1.
- Remove checkout/ composite action; relocated to Cula-Technologies/checkout.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.github/workflows/close-inactive-issues.yml

@@ -0,0 +1,23 @@
+name: Close inactive issues
+
+on:
+  schedule:
+    - cron: "30 8 * * *"
+
+jobs:
+  close-issues:
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      pull-requests: write
+    steps:
+      - uses: actions/stale@v9
+        with:
+          days-before-issue-stale: 200
+          days-before-issue-close: 5
+          stale-issue-label: "stale"
+          stale-issue-message: "This issue is stale because it has been open for 200 days with no activity. Leave a comment to avoid closing this issue in 5 days."
+          close-issue-message: "This issue was closed because it has been inactive for 5 days since being marked as stale."
+          days-before-pr-stale: -1
+          days-before-pr-close: -1
+          repo-token: ${{ secrets.GITHUB_TOKEN }}