fix: Catch BaseException in worker thread to prevent tracebacks on interruption

[szmania]

Summary

Fixes an issue where KeyboardInterrupt exceptions during async completion calls would produce ugly tracebacks and potentially crash the TUI worker thread.

Changes

cecli/tui/worker.py

• Consolidated exception handling in CoderWorker.run() to catch BaseException instead of only asyncio.CancelledError and RuntimeError. This ensures KeyboardInterrupt, SystemExit, and any other unexpected exceptions don't crash the worker thread.
• Removed the now-redundant except KeyboardInterrupt block in _async_run() since the outer BaseException catch in run() already handles it.

cecli/models.py

• Added except KeyboardInterrupt handler in the model's async completion loop to gracefully exit without a traceback when an interrupt occurs mid-request.

Related Issues

• Jira: CLI-29
• Previous attempts: cli-29-interruption-exception-take-1 through take-4

[szmania]

@dwash96 This PR is in draft and should remain so until at least 4 more days of testing have passed to confirm the interruption exception issue no longer occurs. Please do not merge until the testing window is complete.

[szmania]

@dwash96 I've been using this for 3 days incessantly, seems to have fixed the issue. setting to ready for merge