## What changed
- Include `environmentInfo` in the exec-server `initialize` response and seed the Rust client's metadata cache from it.
- Fall back to one lazy `environment/info` request when connecting to older servers that omit initialization metadata, then share the cached result across client clones and session recovery.
- Keep app-server `environment/info` requests uncached so they continue to probe the executor.
## Testing
- Cover initialization metadata, the legacy-server fallback, shared caching, accepted WebSocket environments, and repeated uncached app-server probes.
GitOrigin-RevId: 380132d9db183998d73e8c6b0954e4d70c7e8406
## What changed
- Add `EnvironmentManager::from_accepted_websocket` so embedding hosts can
construct a remote environment from an already accepted and authenticated
Axum WebSocket.
- Add `replace_accepted_websocket` to retire the current transport and resume
the same exec-server session on a host-supplied replacement connection.
- Serialize replacement handoffs, reject overlapping replacements, and release
the handoff claim when a replacement attempt is cancelled or fails.
## Testing
- Cover initial connection validation and immediate environment readiness.
- Verify replacement retry behavior and recovery of a running process and its
output after reconnecting.
GitOrigin-RevId: 1f2ab7bcf7b5abbbece5c101801432dc84a8058d
