## What changed
- Add `codex exec-server forward --connect ws://HOST:PORT` to register an
existing WebSocket exec-server as a remote environment.
- Open a separate destination WebSocket for each authenticated Noise relay
stream and forward complete payloads unchanged in both directions.
- Preserve large messages through WebSocket fragmentation and coordinate
disconnects, close acknowledgements, and pending output delivery.
## Testing
- Cover CLI validation, opaque payload forwarding, disconnect handling, and
destination close behavior.
- Verify commands and large file transfers through the complete relay and
forwarding path.
GitOrigin-RevId: 6e2dccff05b9e3571865611f4d432b0e2b4cdbac
