[T1.8] Closing the app while recording kills the recording unfinalized (and skips the Zoom leave order) #461

Found in review 2026-09-10 (pre-existing, not caused by T1.7). App shutdown kill-trees the core (ForceShutdownMediaCore → DisposeChild → Kill(entireProcessTree:true), MediaCoreSupervisor.cs ~1537-1555). No stop-recording is sent and there is no close-while-recording guard, so the Program moov atom, every ISO writer and any RTMP/SRT egress are killed mid-stream: the recording is unplayable. The Zoom engine is killed as part of the tree, so the documented teardown order (Leave → stop_raw_media → bounded drain → CleanUPSDK) never runs on app close. Kill/WaitForExit failures are swallowed, so 'cleanup succeeded' can be reported with the core alive, and the shell has no job object. Clause 1 (an operator closing the app after a show loses the show recording). Proposed: on close while recording/streaming, ask to stop (or stop and wait for the core to report the destination lifecycle completed, bounded), then an orderly core stop that lets the engine leave; only then TerminateProcess (T1.7).