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/customers/services/admin_customer_service.py

@@ -13,7 +13,6 @@ from sqlalchemy.orm import Session
 
 from app.modules.customers.exceptions import CustomerNotFoundException
 from app.modules.customers.models import Customer
-from app.modules.tenancy.models import Store
 
 logger = logging.getLogger(__name__)
 
@@ -44,8 +43,10 @@ class AdminCustomerService:
         Returns:
             Tuple of (customers list, total count)
         """
+        from app.modules.tenancy.services.store_service import store_service
+
         # Build query
-        query = db.query(Customer).join(Store, Customer.store_id == Store.id)
+        query = db.query(Customer)
 
         # Apply filters
         if store_id:
@@ -66,21 +67,26 @@ class AdminCustomerService:
         # Get total count
         total = query.count()
 
-        # Get paginated results with store info
+        # Get paginated results
         customers = (
-            query.add_columns(Store.name.label("store_name"), Store.store_code)
-            .order_by(Customer.created_at.desc())
+            query.order_by(Customer.created_at.desc())
             .offset(skip)
             .limit(limit)
             .all()
         )
 
+        # Batch-resolve store names
+        store_ids = {c.store_id for c in customers}
+        store_map = {}
+        for sid in store_ids:
+            store = store_service.get_store_by_id_optional(db, sid)
+            if store:
+                store_map[sid] = (store.name, store.store_code)
+
         # Format response
         result = []
-        for row in customers:
-            customer = row[0]
-            store_name = row[1]
-            store_code = row[2]
+        for customer in customers:
+            store_name, store_code = store_map.get(customer.store_id, (None, None))
 
             customer_dict = {
                 "id": customer.id,
@@ -167,18 +173,18 @@ class AdminCustomerService:
         Raises:
             CustomerNotFoundException: If customer not found
         """
-        result = (
+        from app.modules.tenancy.services.store_service import store_service
+
+        customer = (
             db.query(Customer)
-            .join(Store, Customer.store_id == Store.id)
-            .add_columns(Store.name.label("store_name"), Store.store_code)
             .filter(Customer.id == customer_id)
             .first()
         )
 
-        if not result:
+        if not customer:
             raise CustomerNotFoundException(str(customer_id))
 
-        customer = result[0]
+        store = store_service.get_store_by_id_optional(db, customer.store_id)
         return {
             "id": customer.id,
             "store_id": customer.store_id,
@@ -195,8 +201,8 @@ class AdminCustomerService:
             "is_active": customer.is_active,
             "created_at": customer.created_at,
             "updated_at": customer.updated_at,
-            "store_name": result[1],
-            "store_code": result[2],
+            "store_name": store.name if store else None,
+            "store_code": store.store_code if store else None,
         }
 
     def toggle_customer_status(