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/vendor_domain_service.py

@@ -12,25 +12,23 @@ This module provides classes and functions for:
 
 import logging
 import secrets
-from datetime import datetime, timezone
-from typing import List, Optional, Tuple
+from datetime import UTC, datetime
 
-from sqlalchemy import and_
 from sqlalchemy.orm import Session
 
-from app.exceptions import (DNSVerificationException,
-                            DomainAlreadyVerifiedException,
-                            DomainNotVerifiedException,
-                            DomainVerificationFailedException,
-                            InvalidDomainFormatException,
-                            MaxDomainsReachedException,
-                            MultiplePrimaryDomainsException,
-                            ReservedDomainException,
-                            UnauthorizedDomainAccessException,
-                            ValidationException,
-                            VendorDomainAlreadyExistsException,
-                            VendorDomainNotFoundException,
-                            VendorNotFoundException)
+from app.exceptions import (
+    DNSVerificationException,
+    DomainAlreadyVerifiedException,
+    DomainNotVerifiedException,
+    DomainVerificationFailedException,
+    InvalidDomainFormatException,
+    MaxDomainsReachedException,
+    ReservedDomainException,
+    ValidationException,
+    VendorDomainAlreadyExistsException,
+    VendorDomainNotFoundException,
+    VendorNotFoundException,
+)
 from models.database.vendor import Vendor
 from models.database.vendor_domain import VendorDomain
 from models.schema.vendor_domain import VendorDomainCreate, VendorDomainUpdate
@@ -135,7 +133,7 @@ class VendorDomainService:
             logger.error(f"Error adding domain: {str(e)}")
             raise ValidationException("Failed to add domain")
 
-    def get_vendor_domains(self, db: Session, vendor_id: int) -> List[VendorDomain]:
+    def get_vendor_domains(self, db: Session, vendor_id: int) -> list[VendorDomain]:
         """
         Get all domains for a vendor.
 
@@ -272,7 +270,7 @@ class VendorDomainService:
             logger.error(f"Error deleting domain: {str(e)}")
             raise ValidationException("Failed to delete domain")
 
-    def verify_domain(self, db: Session, domain_id: int) -> Tuple[VendorDomain, str]:
+    def verify_domain(self, db: Session, domain_id: int) -> tuple[VendorDomain, str]:
         """
         Verify domain ownership via DNS TXT record.
 
@@ -313,7 +311,7 @@ class VendorDomainService:
                     if txt_value == domain.verification_token:
                         # Verification successful
                         domain.is_verified = True
-                        domain.verified_at = datetime.now(timezone.utc)
+                        domain.verified_at = datetime.now(UTC)
                         db.commit()
                         db.refresh(domain)
 
@@ -419,7 +417,7 @@ class VendorDomainService:
             raise ReservedDomainException(domain, first_part)
 
     def _unset_primary_domains(
-        self, db: Session, vendor_id: int, exclude_domain_id: Optional[int] = None
+        self, db: Session, vendor_id: int, exclude_domain_id: int | None = None
     ) -> None:
         """Unset all primary domains for vendor."""
         query = db.query(VendorDomain).filter(