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/scheduler/jobs.py

@@ -1,4 +1,4 @@
-"""Questionnaire jobs on the demo clock; clinical release disabled by default.
+"""Scheduler on the demo clock: questionnaire jobs when that release is on, else the demo scheduler (#13).
 
 One scheduler per database. PostgreSQL's advisory transaction lock serializes
 workers; an asyncio lock does the same within a SQLite demonstration process.
@@ -22,6 +22,7 @@ from app.db.intake import QuestionnaireTask
 from app.db.session import get_clinical_session
 from app.dialog.contracts import Event, Reply, get_engine
 from app.integrations.base import integrations
+from app.scheduler import demo
 from app.services import monitoring
 from app.services import questionnaire as service
 
@@ -148,6 +149,9 @@ async def run_until_now():
             return
         await service.dispatch_notices()
         if not intake_enabled():
+            # Questionnaire release off → the demo scheduler (doses, check-ins, scales, silence) runs instead.
+            if demo.load_config().enabled:
+                await demo.run_until(clock.now())
             return
         await plan()
         await deliver()
@@ -160,7 +164,7 @@ async def _run():
             await run_until_now()
         except Exception as exc:
             log.error("questionnaire scheduler error=%s", type(exc).__name__)
-        await asyncio.sleep(30)
+        await asyncio.sleep(demo.load_config().tick_seconds)
 
 
 async def start():
@@ -169,7 +173,7 @@ async def start():
         await monitoring.init_clock_persistence()
     except (OSError, SQLAlchemyError) as exc:
         log.error("clock persistence unavailable error=%s", type(exc).__name__)
-    if _worker is None and intake_enabled():
+    if _worker is None and (intake_enabled() or demo.load_config().enabled):
         _worker = asyncio.create_task(_run())