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/orders/routes/api/storefront.py

@@ -22,9 +22,9 @@ from app.api.deps import get_current_customer_api
 from app.core.database import get_db
 from app.exceptions import OrderNotFoundException, VendorNotFoundException
 from app.exceptions.invoice import InvoicePDFNotFoundException
+from app.modules.customers.schemas import CustomerContext
 from app.modules.orders.services import order_service
 from app.services.invoice_service import invoice_service
-from models.database.customer import Customer
 from models.schema.order import (
     OrderDetailResponse,
     OrderListResponse,
@@ -40,7 +40,7 @@ def get_my_orders(
     request: Request,
     skip: int = Query(0, ge=0),
     limit: int = Query(50, ge=1, le=100),
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """
@@ -85,7 +85,7 @@ def get_my_orders(
 def get_order_details(
     request: Request,
     order_id: int = Path(..., description="Order ID", gt=0),
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """
@@ -125,7 +125,7 @@ def get_order_details(
 def download_order_invoice(
     request: Request,
     order_id: int = Path(..., description="Order ID", gt=0),
-    customer: Customer = Depends(get_current_customer_api),
+    customer: CustomerContext = Depends(get_current_customer_api),
     db: Session = Depends(get_db),
 ):
     """