feat(notify-bridge): phase 8 - integration and wiring

Wire all components into a working application:
- Scheduler service: APScheduler loads enabled trackers, polls at intervals
- Watcher service: orchestrates poll -> detect -> notify flow
  - Eagerly loads DB data, then creates aiohttp session for provider
  - Saves tracker state after each poll
  - Logs events to EventLog table
  - Dispatches notifications to targets with template rendering
- Manual trigger endpoint: POST /api/trackers/{id}/trigger
- Scheduler starts on app lifespan startup
- Full end-to-end flow verified: server starts cleanly

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/server/src/notify_bridge_server/services/scheduler.py

@@ -0,0 +1,66 @@
+"""APScheduler-based polling scheduler for trackers."""
+
+from __future__ import annotations
+
+import logging
+
+from apscheduler.schedulers.asyncio import AsyncIOScheduler
+
+_LOGGER = logging.getLogger(__name__)
+
+_scheduler: AsyncIOScheduler | None = None
+
+
+def get_scheduler() -> AsyncIOScheduler:
+    global _scheduler
+    if _scheduler is None:
+        _scheduler = AsyncIOScheduler()
+    return _scheduler
+
+
+async def start_scheduler() -> None:
+    scheduler = get_scheduler()
+    if not scheduler.running:
+        scheduler.start()
+        _LOGGER.info("Scheduler started")
+
+    await _load_tracker_jobs()
+
+
+async def _load_tracker_jobs() -> None:
+    """Load enabled trackers and schedule polling jobs."""
+    from sqlmodel import select
+    from sqlmodel.ext.asyncio.session import AsyncSession
+    from ..database.engine import get_engine
+    from ..database.models import Tracker
+
+    engine = get_engine()
+    scheduler = get_scheduler()
+
+    async with AsyncSession(engine) as session:
+        result = await session.exec(select(Tracker).where(Tracker.enabled == True))
+        trackers = result.all()
+
+    for tracker in trackers:
+        job_id = f"tracker_{tracker.id}"
+        if scheduler.get_job(job_id):
+            continue
+
+        scheduler.add_job(
+            _poll_tracker,
+            "interval",
+            seconds=tracker.scan_interval,
+            id=job_id,
+            args=[tracker.id],
+            replace_existing=True,
+        )
+        _LOGGER.info("Scheduled tracker %d (%s) every %ds", tracker.id, tracker.name, tracker.scan_interval)
+
+
+async def _poll_tracker(tracker_id: int) -> None:
+    """Poll a tracker for changes."""
+    from .watcher import check_tracker
+    try:
+        await check_tracker(tracker_id)
+    except Exception as e:
+        _LOGGER.error("Error polling tracker %d: %s", tracker_id, e)