style: apply black and isort formatting across entire codebase

- Standardize quote style (single to double quotes)
- Reorder and group imports alphabetically
- Fix line breaks and indentation for consistency
- Apply PEP 8 formatting standards

Also updated Makefile to exclude both venv and .venv from code quality checks.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

models/database/__init__.py

@@ -1,17 +1,18 @@
 # models/database/__init__.py
 """Database models package."""
-from .admin import AdminAuditLog, AdminNotification, AdminSetting, PlatformAlert, AdminSession
+from .admin import (AdminAuditLog, AdminNotification, AdminSession,
+                    AdminSetting, PlatformAlert)
 from .base import Base
 from .customer import Customer, CustomerAddress
-from .order import Order, OrderItem
-from .user import User
-from .marketplace_product import MarketplaceProduct
 from .inventory import Inventory
-from .vendor import Vendor, Role, VendorUser
+from .marketplace_import_job import MarketplaceImportJob
+from .marketplace_product import MarketplaceProduct
+from .order import Order, OrderItem
+from .product import Product
+from .user import User
+from .vendor import Role, Vendor, VendorUser
 from .vendor_domain import VendorDomain
 from .vendor_theme import VendorTheme
-from .product import Product
-from .marketplace_import_job import MarketplaceImportJob
 
 __all__ = [
     # Admin-specific models
@@ -34,5 +35,5 @@ __all__ = [
     "MarketplaceImportJob",
     "MarketplaceProduct",
     "VendorDomain",
-    "VendorTheme"
+    "VendorTheme",
 ]