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>

tests/unit/services/test_admin_service.py

@@ -1,14 +1,15 @@
 # tests/unit/services/test_admin_service.py
 import pytest
 
-from app.exceptions import (AdminOperationException, CannotModifySelfException,
-                            UserNotFoundException, UserStatusChangeException,
-                            VendorNotFoundException,
-                            VendorVerificationException)
+from app.exceptions import (
+    AdminOperationException,
+    CannotModifySelfException,
+    UserNotFoundException,
+    UserStatusChangeException,
+    VendorNotFoundException,
+)
 from app.services.admin_service import AdminService
 from app.services.stats_service import stats_service
-from models.database.marketplace_import_job import MarketplaceImportJob
-from models.database.vendor import Vendor
 
 
 @pytest.mark.unit

tests/unit/services/test_auth_service.py

@@ -1,9 +1,11 @@
 # tests/test_auth_service.py
 import pytest
 
-from app.exceptions.auth import (InvalidCredentialsException,
-                                 UserAlreadyExistsException,
-                                 UserNotActiveException)
+from app.exceptions.auth import (
+    InvalidCredentialsException,
+    UserAlreadyExistsException,
+    UserNotActiveException,
+)
 from app.exceptions.base import ValidationException
 from app.services.auth_service import AuthService
 from models.schema.auth import UserLogin, UserRegister

tests/unit/services/test_inventory_service.py

@@ -3,17 +3,16 @@ import uuid
 
 import pytest
 
-from app.exceptions import (InsufficientInventoryException,
-                            InvalidInventoryOperationException,
-                            InvalidQuantityException,
-                            InventoryNotFoundException,
-                            InventoryValidationException,
-                            NegativeInventoryException, ValidationException)
+from app.exceptions import (
+    InsufficientInventoryException,
+    InvalidQuantityException,
+    InventoryNotFoundException,
+    InventoryValidationException,
+)
 from app.services.inventory_service import InventoryService
 from models.database.inventory import Inventory
 from models.database.marketplace_product import MarketplaceProduct
-from models.schema.inventory import (InventoryAdd, InventoryCreate,
-                                     InventoryUpdate)
+from models.schema.inventory import InventoryAdd, InventoryCreate, InventoryUpdate
 
 
 @pytest.mark.unit

tests/unit/services/test_marketplace_service.py

@@ -1,20 +1,21 @@
 # tests/test_marketplace_service.py
 import uuid
-from datetime import datetime
 
 import pytest
 
 from app.exceptions.base import ValidationException
 from app.exceptions.marketplace_import_job import (
-    ImportJobCannotBeCancelledException, ImportJobCannotBeDeletedException,
-    ImportJobNotFoundException, ImportJobNotOwnedException)
-from app.exceptions.vendor import (UnauthorizedVendorAccessException,
-                                   VendorNotFoundException)
-from app.services.marketplace_import_job_service import \
-    MarketplaceImportJobService
+    ImportJobCannotBeCancelledException,
+    ImportJobCannotBeDeletedException,
+    ImportJobNotFoundException,
+    ImportJobNotOwnedException,
+)
+from app.exceptions.vendor import (
+    UnauthorizedVendorAccessException,
+    VendorNotFoundException,
+)
+from app.services.marketplace_import_job_service import MarketplaceImportJobService
 from models.database.marketplace_import_job import MarketplaceImportJob
-from models.database.user import User
-from models.database.vendor import Vendor
 from models.schema.marketplace_import_job import MarketplaceImportJobRequest
 
 

tests/unit/services/test_product_service.py

@@ -1,15 +1,17 @@
 # tests/test_product_service.py
 import pytest
 
-from app.exceptions import (InvalidMarketplaceProductDataException,
-                            MarketplaceProductAlreadyExistsException,
-                            MarketplaceProductNotFoundException,
-                            MarketplaceProductValidationException,
-                            ValidationException)
+from app.exceptions import (
+    InvalidMarketplaceProductDataException,
+    MarketplaceProductAlreadyExistsException,
+    MarketplaceProductNotFoundException,
+    MarketplaceProductValidationException,
+)
 from app.services.marketplace_product_service import MarketplaceProductService
-from models.database.marketplace_product import MarketplaceProduct
-from models.schema.marketplace_product import (MarketplaceProductCreate,
-                                               MarketplaceProductUpdate)
+from models.schema.marketplace_product import (
+    MarketplaceProductCreate,
+    MarketplaceProductUpdate,
+)
 
 
 @pytest.mark.unit

tests/unit/services/test_vendor_service.py

@@ -1,13 +1,16 @@
 # tests/test_vendor_service.py (updated to use custom exceptions)
 import pytest
 
-from app.exceptions import (InvalidVendorDataException,
-                            MarketplaceProductNotFoundException,
-                            MaxVendorsReachedException,
-                            ProductAlreadyExistsException,
-                            UnauthorizedVendorAccessException,
-                            ValidationException, VendorAlreadyExistsException,
-                            VendorNotFoundException)
+from app.exceptions import (
+    InvalidVendorDataException,
+    MarketplaceProductNotFoundException,
+    MaxVendorsReachedException,
+    ProductAlreadyExistsException,
+    UnauthorizedVendorAccessException,
+    ValidationException,
+    VendorAlreadyExistsException,
+    VendorNotFoundException,
+)
 from app.services.vendor_service import VendorService
 from models.schema.product import ProductCreate
 from models.schema.vendor import VendorCreate