- Introduced `StatusGatewayTimeout` (504) for server-side timeouts between HopGate and backend.
- Implemented 504 error page with multilingual support.
- Enhanced `bufio.Reader` usage in JSON decoding to prevent "dtls: buffer too small" errors for large payloads.
- Applied request handling improvements for control domain and timeout scenarios.
- Refactored HTTP tunneling protocol to use `protocol.Envelope` for better extensibility.
- Implemented support for message types including HTTP requests, stream handling, and responses.
- Added common security headers like HSTS and X-Forwarded-For processing for improved security and identity handling.
- Introduced GitHub Actions workflow to build and publish Docker images to GHCR.
- Added new protocol structures for stream-based communication in anticipation of future WebSocket/TCP tunneling.
- Updated `go.sum` to remove unused dependencies and reflect new changes.
- Introduced a new `legoManager` for managing per-domain TLS certificates.
- Implemented ACME HTTP-01 challenge handling with a configurable webroot directory.
- Created `NewLegoManagerFromEnv` to initialize ACME settings from environment variables.
- Added `verifyDomainsResolve` to validate domain DNS resolutions.
- Updated `.gitignore` to include ACME cache and webroot directories.
- Updated `go.mod` and `go.sum` with new dependencies, including `go-acme/lego`.
