[ci skip] f1-stream: add F1 schedule subsystem (Phase 2)

- Fetch 2026 F1 race calendar from jolpica API with all sessions
  (FP1-3, Qualifying, Sprint, Race) and UTC timestamps
- Persist schedule to NFS as JSON, load on startup if fresh
- APScheduler daily refresh at 03:00 UTC
- GET /schedule endpoint with live/upcoming/past session status
- POST /schedule/refresh for manual refresh trigger

stacks/f1-stream/files/backend/main.py

@@ -1,6 +1,54 @@
+"""F1 Streams - FastAPI backend with schedule service."""
+
+import logging
+from contextlib import asynccontextmanager
+
+from apscheduler.schedulers.asyncio import AsyncIOScheduler
+from apscheduler.triggers.cron import CronTrigger
 from fastapi import FastAPI
 
-app = FastAPI(title="F1 Streams")
+from backend.schedule import ScheduleService
+
+logging.basicConfig(
+    level=logging.INFO,
+    format="%(asctime)s %(levelname)s %(name)s: %(message)s",
+)
+logger = logging.getLogger(__name__)
+
+schedule_service = ScheduleService()
+scheduler = AsyncIOScheduler()
+
+
+async def _scheduled_refresh() -> None:
+    """Callback for APScheduler daily refresh."""
+    logger.info("Running scheduled schedule refresh...")
+    await schedule_service.refresh()
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """Startup and shutdown lifecycle handler."""
+    # Startup: load schedule and start background scheduler
+    await schedule_service.initialize()
+
+    scheduler.add_job(
+        _scheduled_refresh,
+        trigger=CronTrigger(hour=3, minute=0, timezone="UTC"),
+        id="daily_schedule_refresh",
+        name="Refresh F1 schedule daily at 03:00 UTC",
+        replace_existing=True,
+    )
+    scheduler.start()
+    logger.info("APScheduler started - daily refresh at 03:00 UTC")
+
+    yield
+
+    # Shutdown
+    scheduler.shutdown(wait=False)
+    logger.info("APScheduler shut down")
+
+
+app = FastAPI(title="F1 Streams", lifespan=lifespan)
 
 
 @app.get("/health")
@@ -13,6 +61,19 @@ async def root():
     return {"service": "f1-streams", "version": "2.0.1"}
 
 
+@app.get("/schedule")
+async def get_schedule():
+    """Return the F1 race schedule for the current season with session statuses."""
+    return schedule_service.get_schedule()
+
+
+@app.post("/schedule/refresh")
+async def refresh_schedule():
+    """Manually trigger a schedule refresh from the jolpica API."""
+    await schedule_service.refresh()
+    return {"status": "refreshed"}
+
+
 if __name__ == "__main__":
     import uvicorn