chore: add release workflow for docker hub

- Added `.github/workflows/release.yml` for multi-platform Docker builds.
- Configured triggers for `main` branch pushes and `v*` tags.
- Uses `docker/metadata-action` for tagging:
  - `latest` is only updated on semantic version tags (e.g., `v1.0.0`).
  - `main` branch pushes are tagged with `main` and commit SHA.
- Supports `linux/amd64` and `linux/arm64`.
- Uses hardcoded `yilingj` username and `DOCKERHUB_TOKEN` secret.

.github/workflows/release.yml

@@ -28,7 +28,7 @@ jobs:
       - name: Log in to Docker Hub
         uses: docker/login-action@v3
         with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          username: yilingj
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       # Extract metadata (tags, labels) for Docker