- Replaced Python execution with a local `python -u runner.py` subprocess and NDJSON stdin/stdout framing.
- Removed shared-gateway architecture, including coordinator lifecycle APIs, `useSharedGateway` wiring, and `jupyter` CLI/actions.
- Simplified setup checks to a plain Python 3 availability probe and removed automatic dependency-install fallbacks.
- Updated kernel cancellation and display processing to use status frames, SIGINT/SIGTERM escalation, and normalized output coercion.
- Added `python-runner` integration and display tests while deleting legacy websocket and kernel lifecycle test suites.
- Removed the JS and Python eval prelude `run` helpers, including their shell execution and timeout/cwd option handling.
- Updated the JS VM helper set to expose `Bun` and removed the deleted `run` entry from the prelude.
- Revised eval docs to drop `run` from the helper surface and note the new JS `Bun` global.