- Replaced single-envelope JSON model with a stream/frame-based protocol using `StreamOpen`, `StreamData`, and `StreamClose` for chunked transmission.
- Added application-level ARQ with selective retransmission (`StreamAck`) for reliability over DTLS/UDP.
- Defined MTU-safe chunk sizes and sequence-based flow control to handle large HTTP bodies effectively.
- Updated `internal/protocol` for structured stream message handling, including ACK/NACK support.
- Documented potential transition to binary serialization for performance optimization.
- 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.
