refactor: fix architecture violations with provider patterns and dependency inversion

Major changes:
- Add AuditProvider protocol for cross-module audit logging
- Move customer order operations to orders module (dependency inversion)
- Add customer order metrics via MetricsProvider pattern
- Fix missing db parameter in get_admin_context() calls
- Move ProductMedia relationship to catalog module (proper ownership)
- Add marketplace breakdown stats to marketplace_widgets

New files:
- contracts/audit.py - AuditProviderProtocol
- core/services/audit_aggregator.py - Aggregates audit providers
- monitoring/services/audit_provider.py - Monitoring audit implementation
- orders/services/customer_order_service.py - Customer order operations
- orders/routes/api/vendor_customer_orders.py - Customer order endpoints
- catalog/services/product_media_service.py - Product media service
- Architecture documentation for patterns

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

app/modules/customers/schemas/customer.py

@@ -244,7 +244,12 @@ class VendorCustomerListResponse(BaseModel):
 
 
 class CustomerDetailResponse(BaseModel):
-    """Detailed customer response for vendor management."""
+    """Detailed customer response for vendor management.
+
+    Note: Order-related statistics (total_orders, total_spent, last_order_date)
+    are available via the orders module endpoint:
+    GET /api/vendor/customers/{customer_id}/order-stats
+    """
 
     id: int | None = None
     vendor_id: int | None = None
@@ -255,9 +260,6 @@ class CustomerDetailResponse(BaseModel):
     customer_number: str | None = None
     marketing_consent: bool | None = None
     preferred_language: str | None = None
-    last_order_date: datetime | None = None
-    total_orders: int | None = None
-    total_spent: Decimal | None = None
     is_active: bool | None = None
     created_at: datetime | None = None
     updated_at: datetime | None = None