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/customer.py

@@ -1,8 +1,12 @@
 from datetime import datetime
 from decimal import Decimal
-from sqlalchemy import Column, Integer, String, Boolean, DateTime, ForeignKey, Text, JSON, Numeric
+
+from sqlalchemy import (JSON, Boolean, Column, DateTime, ForeignKey, Integer,
+                        Numeric, String, Text)
 from sqlalchemy.orm import relationship
+
 from app.core.database import Base
+
 from .base import TimestampMixin
 
 
@@ -11,12 +15,16 @@ class Customer(Base, TimestampMixin):
 
     id = Column(Integer, primary_key=True, index=True)
     vendor_id = Column(Integer, ForeignKey("vendors.id"), nullable=False)
-    email = Column(String(255), nullable=False, index=True)  # Unique within vendor scope
+    email = Column(
+        String(255), nullable=False, index=True
+    )  # Unique within vendor scope
     hashed_password = Column(String(255), nullable=False)
     first_name = Column(String(100))
     last_name = Column(String(100))
     phone = Column(String(50))
-    customer_number = Column(String(100), nullable=False, index=True)  # Vendor-specific ID
+    customer_number = Column(
+        String(100), nullable=False, index=True
+    )  # Vendor-specific ID
     preferences = Column(JSON, default=dict)
     marketing_consent = Column(Boolean, default=False)
     last_order_date = Column(DateTime)