## What changed
- Enforce an 8 KiB encoded-message limit for requests, unrecognized notifications, and malformed messages received by exec-server clients over stdio, WebSocket, relay, and Noise relay transports.
- Allow process output, exit, close, and HTTP request body notifications up to 2 MiB. Keep responses and errors subject to existing transport limits, and preserve executor-side request limits.
- Read stdio stderr in chunks of at most 8 KiB.
- Drop outgoing server-request `tracestate` values larger than 512 bytes while preserving `traceparent`.
## Testing
Add regression coverage for oversized requests across transports, malformed messages, requests wrapped in `RawValue`, fragmented Noise messages, large responses, streamed notifications, and trace-context preservation.
GitOrigin-RevId: 3fb87b6dc334296985ef40983d7276acfe9b9796
