Rename GITEA_CLONE_URL to G_CLONE_URL in all checkout steps
and update GITEA_TOKEN and GITEA_USERNAME to G_TOKEN and
G_USERNAME for Docker registry authentication. This standardizes
secret naming across the CI/CD pipeline.
Add GitHub Actions workflow that performs linting with golangci-lint,
formats check, cross-compilation for linux/amd64, linux/arm64, and
windows/amd64, and multi-platform docker image publishing to Gitea
registry on pushes to main/master branches.
- Migrate IP-based temporary whitelisting from file to SQLite storage
- Add REST API endpoints for managing temporary and permanent whitelists
- Create `.env.example` with required environment variables
- Document API endpoints in README.md and docs/api.md
- Add new dependency `modernc.org/sqlite` for SQLite support
- Update deployment and security documentation
