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>

app/services/snapshot.py

@@ -0,0 +1,93 @@
+"""Patient snapshot for the rules engine, assembled from the clinical DB (ADR-007).
+
+Maps storage names to `app.core.rules` names (`sleep_bucket` → `sleep_hours_bucket`, `alcohol_bucket` →
+`alcohol`), derives age from `birth_year` and the therapy day from `therapy_start`. Time comes in as `as_of`
+(from `app.core.clock`), never from the wall clock. Must not import `app.db.identity` (guardrail #5).
+"""
+
+from datetime import datetime, timedelta
+from typing import Any, get_args
+
+from sqlalchemy import func, select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.core.rules import (
+    CssrsRisk,
+    DailyCheckin,
+    DoseRecord,
+    Module,
+    PatientSnapshot,
+    ScalePoint,
+)
+from app.db import repo
+from app.db.clinical import Dose, Message, PatientProfile
+
+# Risk screens are stored as scale results but reach the rules as `cssrs_risk`, not as scale points.
+CSSRS_SCALES = frozenset({"cssrs_screen", "cssrs"})
+# A C-SSRS result counts as the current risk for this long (same window as PHQ-9 item 9 and the dialog's
+# C-SSRS cooldown): one old "high" must not restart the crisis protocol after the doctor has acted on it.
+CSSRS_RECENT = timedelta(hours=24)
+# Unknown sex/age fall back to the more cautious option: lower AUDIT-C cut-off, young-adult monitoring.
+_UNKNOWN_SEX = "f"
+_UNKNOWN_AGE = 0
+
+_MODULES = frozenset(get_args(Module))
+_CSSRS_RISKS = frozenset(get_args(CssrsRisk))
+
+
+def _cssrs_risk(results: list[Any], as_of: datetime) -> CssrsRisk | None:
+    recent = [r for r in results if r.scale in CSSRS_SCALES and as_of - CSSRS_RECENT < r.ts <= as_of]
+    if not recent:
+        return None
+    severity = recent[-1].severity
+    return severity if severity in _CSSRS_RISKS else None
+
+
+async def build_snapshot(
+    session: AsyncSession, token: str, as_of: datetime, *, profile: PatientProfile | None = None
+) -> PatientSnapshot | None:
+    """Snapshot of everything the rules may look at; None if the patient has no clinical profile."""
+    profile = profile or await repo.get_profile(session, token)
+    if profile is None:
+        return None
+
+    checkins = [
+        DailyCheckin(
+            day=c.day,
+            mood=c.mood,
+            med_taken=c.med_taken,
+            sleep_hours_bucket=c.sleep_bucket,  # type: ignore[arg-type]
+            alcohol=c.alcohol_bucket,  # type: ignore[arg-type]
+            side_effects=list(c.side_effects or []),
+            quit_intent=bool(c.quit_intent),
+            nightmares=c.nightmares,
+        )
+        for c in await repo.list_checkins(session, token)
+    ]
+    results = [r for r in await repo.list_scale_results(session, token) if r.complete]
+    doses = (await session.scalars(select(Dose).where(Dose.token == token).order_by(Dose.planned_at))).all()
+    last_in = await session.scalar(
+        select(func.max(Message.ts)).where(Message.token == token, Message.direction == "in")
+    )
+    state = await repo.get_dialog_state(session, token)
+    facts = (state.data.get("facts") or {}) if state is not None else {}
+
+    return PatientSnapshot(
+        token=token,
+        as_of=as_of,
+        age=as_of.year - profile.birth_year if profile.birth_year else _UNKNOWN_AGE,
+        sex=profile.sex if profile.sex in ("m", "f") else _UNKNOWN_SEX,  # type: ignore[arg-type]
+        modules={m for m in profile.modules or [] if m in _MODULES},  # type: ignore[misc]
+        therapy_day=(as_of.date() - profile.therapy_start).days if profile.therapy_start else 0,
+        checkins=checkins,
+        scale_results=[
+            ScalePoint(scale=r.scale, ts=r.ts, total=r.total, item9=r.item9, scheduled=r.scheduled)
+            for r in results
+            if r.scale not in CSSRS_SCALES
+        ],
+        doses=[DoseRecord(planned_at=d.planned_at, status=d.status) for d in doses],  # type: ignore[arg-type]
+        cssrs_risk=_cssrs_risk(results, as_of),
+        weapon_access=facts.get("weapon_access"),
+        last_patient_message_at=last_in,
+        open_alert_codes=await repo.open_alert_codes(session, token),
+    )