The delegated_task_status recording ends with the recorder closing the
app-server while the parent turn is still open. The MCP integration test keeps
acting as that parent afterwards, so replaying the exit now (correctly) fails
the parent run and task_status reports parent_not_active. Drop the recorded
exit in that test's loader instead of changing what the app-server exit does.

Also assert that a dead process fails the event stream with
ProviderAdapterEventStreamError, since a clean end reads as manual_shutdown.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>