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/services/contracts.py

@@ -0,0 +1,47 @@
+"""Monitoring service contract (frozen, #34).
+
+Split of responsibilities (ADR-007):
+  * Lane B (#38) implements `MonitoringService`: builds a patient snapshot from the DB, runs the deterministic
+    rules (`app.core.rules.evaluate`), persists `alert`/`crisis` actions and notifies the doctor itself.
+  * It returns only the *dialog* actions (schedule_scale, med_info, reach_out, show_safety_plan, suggest_visit,
+    crisis) so the engine (lane A, #10) can react in the conversation. The engine never creates alerts.
+"""
+
+from collections.abc import Callable
+from importlib import import_module, util
+from typing import Protocol
+
+from app.core.rules import Action
+
+
+class MonitoringService(Protocol):
+    async def after_data_change(self, token: str) -> list[Action]: ...
+
+    async def is_in_crisis(self, token: str) -> bool:
+        """True while an `acute` alert is open (not acked by the doctor) — FSM stays in `crisis`."""
+        ...
+
+
+class NoopMonitoring:
+    """Placeholder until #38 lands."""
+
+    async def after_data_change(self, token: str) -> list[Action]:
+        return []
+
+    async def is_in_crisis(self, token: str) -> bool:
+        return False
+
+
+_factory: Callable[[], MonitoringService] = NoopMonitoring
+
+
+def register_monitoring(factory: Callable[[], MonitoringService]) -> None:
+    global _factory
+    _factory = factory
+
+
+def get_monitoring() -> MonitoringService:
+    # find_spec instead of try/except ImportError: real import errors inside the module must surface.
+    if util.find_spec("app.services.monitoring") is not None:
+        import_module("app.services.monitoring")
+    return _factory()