feat(services): add planner.py orchestration helpers

app/services/meal_plan/planner.py

@@ -0,0 +1,26 @@
+# app/services/meal_plan/planner.py
+"""Plan and slot orchestration — thin layer over Store.
+
+No FastAPI imports. Provides helpers used by the API endpoint.
+"""
+from __future__ import annotations
+
+from app.db.store import Store
+from app.models.schemas.meal_plan import VALID_MEAL_TYPES
+
+
+def create_plan(store: Store, week_start: str, meal_types: list[str]) -> dict:
+    """Create a plan, filtering meal_types to valid values only."""
+    valid = [t for t in meal_types if t in VALID_MEAL_TYPES]
+    if not valid:
+        valid = ["dinner"]
+    return store.create_meal_plan(week_start, valid)
+
+
+def get_plan_with_slots(store: Store, plan_id: int) -> dict | None:
+    """Return a plan row with its slots list attached, or None."""
+    plan = store.get_meal_plan(plan_id)
+    if plan is None:
+        return None
+    slots = store.get_plan_slots(plan_id)
+    return {**plan, "slots": slots}