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/order.py

@@ -1,6 +1,8 @@
 # models/database/order.py
 from datetime import datetime
-from sqlalchemy import Column, DateTime, Float, ForeignKey, Integer, String, Text, Boolean
+
+from sqlalchemy import (Boolean, Column, DateTime, Float, ForeignKey, Integer,
+                        String, Text)
 from sqlalchemy.orm import relationship
 
 from app.core.database import Base
@@ -9,11 +11,14 @@ from models.database.base import TimestampMixin
 
 class Order(Base, TimestampMixin):
     """Customer orders."""
+
     __tablename__ = "orders"
 
     id = Column(Integer, primary_key=True, index=True)
     vendor_id = Column(Integer, ForeignKey("vendors.id"), nullable=False, index=True)
-    customer_id = Column(Integer, ForeignKey("customers.id"), nullable=False, index=True)
+    customer_id = Column(
+        Integer, ForeignKey("customers.id"), nullable=False, index=True
+    )
 
     order_number = Column(String, nullable=False, unique=True, index=True)
 
@@ -30,8 +35,12 @@ class Order(Base, TimestampMixin):
     currency = Column(String, default="EUR")
 
     # Addresses (stored as IDs)
-    shipping_address_id = Column(Integer, ForeignKey("customer_addresses.id"), nullable=False)
-    billing_address_id = Column(Integer, ForeignKey("customer_addresses.id"), nullable=False)
+    shipping_address_id = Column(
+        Integer, ForeignKey("customer_addresses.id"), nullable=False
+    )
+    billing_address_id = Column(
+        Integer, ForeignKey("customer_addresses.id"), nullable=False
+    )
 
     # Shipping
     shipping_method = Column(String, nullable=True)
@@ -50,8 +59,12 @@ class Order(Base, TimestampMixin):
     # Relationships
     vendor = relationship("Vendor")
     customer = relationship("Customer", back_populates="orders")
-    items = relationship("OrderItem", back_populates="order", cascade="all, delete-orphan")
-    shipping_address = relationship("CustomerAddress", foreign_keys=[shipping_address_id])
+    items = relationship(
+        "OrderItem", back_populates="order", cascade="all, delete-orphan"
+    )
+    shipping_address = relationship(
+        "CustomerAddress", foreign_keys=[shipping_address_id]
+    )
     billing_address = relationship("CustomerAddress", foreign_keys=[billing_address_id])
 
     def __repr__(self):
@@ -60,6 +73,7 @@ class Order(Base, TimestampMixin):
 
 class OrderItem(Base, TimestampMixin):
     """Individual items in an order."""
+
     __tablename__ = "order_items"
 
     id = Column(Integer, primary_key=True, index=True)