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/api/v1/vendor/marketplace.py

@@ -5,22 +5,22 @@ Vendor context is automatically injected by middleware.
 """
 
 import logging
-from typing import List, Optional
 
 from fastapi import APIRouter, BackgroundTasks, Depends, Query
 from sqlalchemy.orm import Session
 
 from app.api.deps import get_current_vendor_api
 from app.core.database import get_db
-from app.services.marketplace_import_job_service import \
-    marketplace_import_job_service
+from app.services.marketplace_import_job_service import marketplace_import_job_service
 from app.tasks.background_tasks import process_marketplace_import
 from middleware.decorators import rate_limit
 from middleware.vendor_context import require_vendor_context  # IMPORTANT
 from models.database.user import User
 from models.database.vendor import Vendor
-from models.schema.marketplace_import_job import (MarketplaceImportJobRequest,
-                                                  MarketplaceImportJobResponse)
+from models.schema.marketplace_import_job import (
+    MarketplaceImportJobRequest,
+    MarketplaceImportJobResponse,
+)
 
 router = APIRouter()
 logger = logging.getLogger(__name__)
@@ -93,9 +93,9 @@ def get_marketplace_import_status(
     return marketplace_import_job_service.convert_to_response_model(job)
 
 
-@router.get("/imports", response_model=List[MarketplaceImportJobResponse])
+@router.get("/imports", response_model=list[MarketplaceImportJobResponse])
 def get_marketplace_import_jobs(
-    marketplace: Optional[str] = Query(None, description="Filter by marketplace"),
+    marketplace: str | None = Query(None, description="Filter by marketplace"),
     skip: int = Query(0, ge=0),
     limit: int = Query(50, ge=1, le=100),
     vendor: Vendor = Depends(require_vendor_context()),