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/user.py

@@ -10,16 +10,18 @@ ROLE CLARIFICATION:
 - Vendor-specific roles (manager, staff, etc.) are stored in VendorUser.role
 - Customers are NOT in the User table - they use the Customer model
 """
-from sqlalchemy import Boolean, Column, DateTime, Integer, String, Enum
-from sqlalchemy.orm import relationship
 import enum
 
+from sqlalchemy import Boolean, Column, DateTime, Enum, Integer, String
+from sqlalchemy.orm import relationship
+
 from app.core.database import Base
 from models.database.base import TimestampMixin
 
 
 class UserRole(str, enum.Enum):
     """Platform-level user roles."""
+
     ADMIN = "admin"  # Platform administrator
     VENDOR = "vendor"  # Vendor owner or team member
 
@@ -44,12 +46,12 @@ class User(Base, TimestampMixin):
     last_login = Column(DateTime, nullable=True)
 
     # Relationships
-    marketplace_import_jobs = relationship("MarketplaceImportJob", back_populates="user")
+    marketplace_import_jobs = relationship(
+        "MarketplaceImportJob", back_populates="user"
+    )
     owned_vendors = relationship("Vendor", back_populates="owner")
     vendor_memberships = relationship(
-        "VendorUser",
-        foreign_keys="[VendorUser.user_id]",
-        back_populates="user"
+        "VendorUser", foreign_keys="[VendorUser.user_id]", back_populates="user"
     )
 
     def __repr__(self):
@@ -84,8 +86,7 @@ class User(Base, TimestampMixin):
             return True
         # Check if team member
         return any(
-            vm.vendor_id == vendor_id and vm.is_active
-            for vm in self.vendor_memberships
+            vm.vendor_id == vendor_id and vm.is_active for vm in self.vendor_memberships
         )
 
     def get_vendor_role(self, vendor_id: int) -> str: