refactor: modernize code quality tooling with Ruff

- Replace black, isort, and flake8 with Ruff (all-in-one linter and formatter)
- Add comprehensive pyproject.toml configuration
- Simplify Makefile code quality targets
- Configure exclusions for venv/.venv in pyproject.toml
- Auto-fix 1,359 linting issues across codebase

Benefits:
- Much faster builds (Ruff is written in Rust)
- Single tool replaces multiple tools
- More comprehensive rule set (UP, B, C4, SIM, PIE, RET, Q)
- All configuration centralized in pyproject.toml
- Better import sorting and formatting consistency

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

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

app/services/customer_service.py

@@ -7,22 +7,22 @@ with complete vendor isolation.
 """
 
 import logging
-from datetime import datetime, timedelta
-from typing import Any, Dict, Optional
+from datetime import UTC, datetime, timedelta
+from typing import Any
 
 from sqlalchemy import and_
 from sqlalchemy.orm import Session
 
-from app.exceptions.customer import (CustomerAlreadyExistsException,
-                                     CustomerNotActiveException,
-                                     CustomerNotFoundException,
-                                     CustomerValidationException,
-                                     DuplicateCustomerEmailException,
-                                     InvalidCustomerCredentialsException)
-from app.exceptions.vendor import (VendorNotActiveException,
-                                   VendorNotFoundException)
+from app.exceptions.customer import (
+    CustomerNotActiveException,
+    CustomerNotFoundException,
+    CustomerValidationException,
+    DuplicateCustomerEmailException,
+    InvalidCustomerCredentialsException,
+)
+from app.exceptions.vendor import VendorNotActiveException, VendorNotFoundException
 from app.services.auth_service import AuthService
-from models.database.customer import Customer, CustomerAddress
+from models.database.customer import Customer
 from models.database.vendor import Vendor
 from models.schema.auth import UserLogin
 from models.schema.customer import CustomerRegister, CustomerUpdate
@@ -128,7 +128,7 @@ class CustomerService:
 
     def login_customer(
         self, db: Session, vendor_id: int, credentials: UserLogin
-    ) -> Dict[str, Any]:
+    ) -> dict[str, Any]:
         """
         Authenticate customer and generate JWT token.
 
@@ -177,13 +177,13 @@ class CustomerService:
 
         # Generate JWT token with customer context
         # Use auth_manager directly since Customer is not a User model
-        from datetime import datetime, timedelta, timezone
+        from datetime import datetime
 
         from jose import jwt
 
         auth_manager = self.auth_service.auth_manager
         expires_delta = timedelta(minutes=auth_manager.token_expire_minutes)
-        expire = datetime.now(timezone.utc) + expires_delta
+        expire = datetime.now(UTC) + expires_delta
 
         payload = {
             "sub": str(customer.id),
@@ -191,7 +191,7 @@ class CustomerService:
             "vendor_id": vendor_id,
             "type": "customer",
             "exp": expire,
-            "iat": datetime.now(timezone.utc),
+            "iat": datetime.now(UTC),
         }
 
         token = jwt.encode(
@@ -239,7 +239,7 @@ class CustomerService:
 
     def get_customer_by_email(
         self, db: Session, vendor_id: int, email: str
-    ) -> Optional[Customer]:
+    ) -> Customer | None:
         """
         Get customer by email (vendor-scoped).