## Summary

- What changed and why?

## Checklist

- [ ] Unit tests updated/added
- [ ] Ran local smoke tests (HTTP routes, Socket.IO exec/resize)
- [ ] No public route changes (paths, query params)
- [ ] No Socket.IO event name/payload changes
- [ ] `npm run typecheck` (if configured) passes
- [ ] `npm test`/`vitest` passes
- [ ] Updated docs (TS-MIGRATTE.md or relevant DOCS/* if needed)

## Checkpoint (optional)

Add `[checkpoint]` to the PR title to trigger a manual approval gate in CI for human functional testing.