- Added a persistent asyncio event loop and coroutine-aware compiled-code execution for runner cells.
- Enabled compiling notebook cells with top-level await flags and awaiting coroutine results before rendering.
- Added an integration test confirming top-level await works across kernel cells with preserved state.
- 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.
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