refactor(arch): use CustomerContext schema for dependency injection

Phase 5 of storefront restructure plan - fix direct model imports in
API routes by using schemas for dependency injection.

Created CustomerContext schema:
- Lightweight Pydantic model for customer data in API routes
- Populated from Customer DB model in auth dependency
- Contains all fields needed by storefront routes
- Includes from_db_model() factory method

Updated app/api/deps.py:
- _validate_customer_token now returns CustomerContext instead of Customer
- Updated docstrings for all customer auth functions

Updated module storefront routes:
- customers: Uses CustomerContext for profile/address endpoints
- orders: Uses CustomerContext for order history endpoints
- checkout: Uses CustomerContext for order placement
- messaging: Uses CustomerContext for messaging endpoints

This enforces the layered architecture (Routes → Services → Models)
by ensuring API routes never import database models directly.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/modules/customers/routes/api/storefront.py

@@ -24,13 +24,13 @@ from app.api.deps import get_current_customer_api
 from app.core.database import get_db
 from app.core.environment import should_use_secure_cookies
 from app.exceptions import ValidationException, VendorNotFoundException
+from app.modules.customers.schemas import CustomerContext
 from app.modules.customers.services import (
     customer_address_service,
     customer_service,
 )
 from app.services.auth_service import AuthService
 from app.services.email_service import EmailService
-from models.database.customer import Customer
 from models.database.password_reset_token import PasswordResetToken
 from models.schema.auth import (
     LogoutResponse,
@@ -371,7 +371,7 @@ def reset_password(
 
 @router.get("/profile", response_model=CustomerResponse)  # authenticated
 def get_profile(
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """
@@ -390,7 +390,7 @@ def get_profile(
 @router.put("/profile", response_model=CustomerResponse)
 def update_profile(
     update_data: CustomerUpdate,
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """
@@ -444,7 +444,7 @@ def update_profile(
 @router.put("/profile/password", response_model=dict)
 def change_password(
     password_data: CustomerPasswordChange,
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """
@@ -492,7 +492,7 @@ def change_password(
 @router.get("/addresses", response_model=CustomerAddressListResponse)  # authenticated
 def list_addresses(
     request: Request,
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """
@@ -528,7 +528,7 @@ def list_addresses(
 def get_address(
     request: Request,
     address_id: int = Path(..., description="Address ID", gt=0),
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """
@@ -561,7 +561,7 @@ def get_address(
 def create_address(
     request: Request,
     address_data: CustomerAddressCreate,
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """
@@ -610,7 +610,7 @@ def update_address(
     request: Request,
     address_data: CustomerAddressUpdate,
     address_id: int = Path(..., description="Address ID", gt=0),
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """
@@ -654,7 +654,7 @@ def update_address(
 def delete_address(
     request: Request,
     address_id: int = Path(..., description="Address ID", gt=0),
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """
@@ -691,7 +691,7 @@ def delete_address(
 def set_address_default(
     request: Request,
     address_id: int = Path(..., description="Address ID", gt=0),
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """