chore(core): stage 1 contracts — dialog, API schemas + fixtures, integrations, monitoring, modules

Freeze interfaces between lanes A (bot), B (backend), C (dashboard) so three developers work in
parallel without touching each other's files: dialog Event/Reply + engine registry with echo stub,
integration protocols with in-memory defaults, MonitoringService with noop stub, /api/v1 schemas
with fixture-backed routes, frozen main.py wiring, config/modules.yaml + due_scales(), DAR-5,
tzdata, Andrey trajectory, lanes in WORKFLOW, ADR-010.

Refs #34

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

app/scheduler/jobs.py

@@ -0,0 +1,13 @@
+"""Scheduler on the (virtual) demo clock — stub until #13. Called from app.main lifespan."""
+
+
+async def start() -> None:
+    """Start periodic ticking (#13)."""
+
+
+async def stop() -> None:
+    """Stop the scheduler (#13)."""
+
+
+async def run_until_now() -> None:
+    """Replay all due events up to `app.core.clock.now()` in order, idempotently (#13)."""