refactor(arch): eliminate all cross-module model imports in service layer

Enforce MOD-025/MOD-026 rules: zero top-level cross-module model imports
remain in any service file. All 66 files migrated using deferred import
patterns (method-body, _get_model() helpers, instance-cached self._Model)
and new cross-module service methods in tenancy. Documentation updated
with Pattern 6 (deferred imports), migration plan marked complete, and
violations status reflects 84→0 service-layer violations.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/orders/services/order_features.py

@@ -143,18 +143,20 @@ class OrderFeatureProvider:
         platform_id: int,
     ) -> list[FeatureUsage]:
         from app.modules.orders.models.order import Order
-        from app.modules.tenancy.models import Store, StorePlatform
+        from app.modules.tenancy.services.platform_service import platform_service
+        from app.modules.tenancy.services.store_service import store_service
 
         now = datetime.now(UTC)
         period_start = now.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
 
+        merchant_stores = store_service.get_stores_by_merchant_id(db, merchant_id)
+        platform_store_ids = platform_service.get_store_ids_for_platform(db, platform_id)
+        store_ids = [s.id for s in merchant_stores if s.id in platform_store_ids]
+
         count = (
             db.query(func.count(Order.id))
-            .join(Store, Order.store_id == Store.id)
-            .join(StorePlatform, Store.id == StorePlatform.store_id)
             .filter(
-                Store.merchant_id == merchant_id,
-                StorePlatform.platform_id == platform_id,
+                Order.store_id.in_(store_ids),
                 Order.created_at >= period_start,
             )
             .scalar()