fix(scheduler-sidecar): host AsyncIOScheduler inside a real event loop#104
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Prod crash-loop: RuntimeError: no running event loop from apscheduler/schedulers/asyncio.py, raised inside start_scheduler() -> AsyncIOScheduler.start(). It ran fine in-process before because it bound to uvicorn's already-running loop; the sidecar's sync _run() called it with no loop at all, so nothing scheduled in prod and the container restarted forever. DB wait stays synchronous (plain blocking I/O, no loop needed). Everything from start_scheduler() onward now runs inside asyncio.run(_amain()): signal handlers install via loop.add_signal_handler (falling back to signal.signal + call_soon_threadsafe where add_signal_handler isn't implemented), start_scheduler() runs with a loop bound, an asyncio.Event gates shutdown, then stop_scheduler(). core/scheduler.py is untouched. New regression test stubs start_scheduler() to call asyncio.get_running_loop() itself and asserts it doesn't raise — verified against the previous synchronous implementation that this reproduces the exact prod RuntimeError, and passes against the fix. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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#103's sidecar crash-loops on prod:
RuntimeError: no running event loop.core/scheduler.pyuses AsyncIOScheduler — inside the gunicorn workers it bound to uvicorn's loop; the standalone entrypoint was synchronous, sostart_scheduler()had no loop to bind. The unit tests had mockedstart_scheduler, hiding exactly this integration contract.scheduler_main.py: DB-wait stays sync, thenasyncio.run(_amain())— signal handlers vialoop.add_signal_handler(signal.signal fallback),start_scheduler()under the running loop, await shutdown event,stop_scheduler(), exit 0.core/scheduler.pyuntouched.start_schedulerstub callsasyncio.get_running_loop()itself — verified to FAIL against the previous sync implementation before the fix.Prod is currently scheduler-dark (workers gated off per #103, sidecar looping) — this restores it.
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