feat(backend): monitoring service — snapshot, rules, alerts, status colour, clock persistence

- app/services/snapshot.py: PatientSnapshot from the clinical DB (field mapping, age, therapy day,
  recent C-SSRS risk, weapon access from dialog facts)
- app/services/monitoring.py: RuleMonitoring registered via register_monitoring; persists alert/crisis
  actions, crisis_acute audit, enhanced_monitoring flag, cached status_color, notifies the doctor (and
  the doctor on duty for crises) after commit; a running crisis is not restarted
- demo clock offset persisted in clock_state, restored on scheduler start
- tests: Andrey's 13 days through the service → G G G Y Y G G G G Y Y Y R

Refs #38

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

tests/test_contracts.py

@@ -1,14 +1,24 @@
 from fastapi.testclient import TestClient
 
+from app.db import session
+from app.db.bootstrap import init_db
 from app.dialog.contracts import Event, get_engine
 from app.main import app
 from app.services.contracts import get_monitoring
 
+MEM = "sqlite+aiosqlite:///:memory:"
+
 
 async def test_stubs_are_usable() -> None:
-    replies = await get_engine().handle("tok", Event(type="text", text="привет"))
-    assert replies and replies[0].text
-    assert await get_monitoring().after_data_change("tok") == []
+    await session.configure(identity_url=MEM, clinical_url=MEM)
+    await init_db()
+    try:
+        replies = await get_engine().handle("tok", Event(type="text", text="привет"))
+        assert replies and replies[0].text
+        assert await get_monitoring().after_data_change("tok") == []  # unknown patient → no actions
+        assert await get_monitoring().is_in_crisis("tok") is False
+    finally:
+        await session.configure()
 
 
 def test_api_fixture_routes() -> None: