feat(backend): demo scheduler on the virtual clock — doses, missed, check-ins, scales, silence

- app/scheduler/demo.py: run_until(now) replays due and fresh events in time order: dose rows +
  med_reminder, missed after 2 h without an answer → monitoring, daily_checkin, scale_due by the
  config/modules.yaml schedules, daily monitoring pass (silence, missed doses) → reach_out/scale_due
- idempotent via scheduler_events (unique token+key); stale events are not sent; no contact without
  consent or during an open crisis
- config/scheduler.yaml: times and windows; runs while the questionnaire release is off
- POST /demo/clock/advance replays the scheduler up to the new time

Refs #13

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

app/db/bootstrap.py

@@ -5,6 +5,7 @@ The only module (besides registration code) that touches both schemas — and on
 
 from app.db import audit as _audit  # noqa: F401  (registers audit_log in clinical metadata)
 from app.db import intake as _intake  # noqa: F401
+from app.db import scheduler as _scheduler  # noqa: F401
 from app.db.clinical import ClinicalBase
 from app.db.identity import IdentityBase
 from app.db.session import clinical_engine, identity_engine