`emit_live_result` already detected a lost result_channel listener: it
sent a one-shot status warning and from then on short-circuited future
result sends. But if the status_channel listener was also gone — which
is what happens when the user closes the main window without calling
stop_live_transcription_session — the worker kept polling inflight
inference every 10 ms forever, holding a model loaded on the GPU and
keeping the WAV writer file handle open until the process exited.
When the warning send to status_channel also returns Err, the entire
frontend channel pair is dead. Self-assert stop_flag from inside
emit_live_result so the worker drains and exits cleanly. Existing user-
initiated stop semantics are unchanged.
- Threaded `stop_flag: &Arc<AtomicBool>` through `emit_live_result` and
the free `poll_inference` (instance method already had access via
`self.stop_flag`).
- Existing `result_listener_loss_is_warned_once_*` test updated to pass
a stop_flag and assert it stays false when only result_channel fails.
- New test `dead_result_and_status_channels_self_assert_stop_flag` proves
the self-stop fires when both channels Err.
(src-tauri doesn't build in the audit sandbox — needs webkit2gtk; CI
cross-platform compiles it.)
https://claude.ai/code/session_0189xUb6ie6t9qHkzatGZ9Rb
73f8c45f86