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>

save/action.yml

@@ -1,6 +1,6 @@
-name: 'Save Cache with GCS Support'
-description: 'Save cache artifacts to Google Cloud Storage or GitHub with automatic fallback'
-author: 'danySam'
+name: 'Save a cache'
+description: 'Save Cache artifacts like dependencies and build outputs to improve workflow execution time'
+author: 'GitHub'
 inputs:
   path:
     description: 'A list of files, directories, and wildcard patterns to cache'