BREAKING CHANGE: Promote beta features to stable release for v5.0.0
This commit ensures the stable release gets properly published to NPM and GitHub releases.
- Add contents:write permission for GitHub Actions
- Configure git to use GITHUB_TOKEN for authentication
- Set remote URL with access token for push operations
- This should resolve the 403 permission denied error
- Add GitHub Actions workflow for one-click promotion to stable
- Supports patch/minor/major version bumps
- Automatically merges main to stable and handles version updates
- Eliminates manual git operations for stable releases
