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/admin/marketplace.py

@@ -4,7 +4,6 @@ Marketplace import job monitoring endpoints for admin.
 """
 
 import logging
-from typing import List, Optional
 
 from fastapi import APIRouter, Depends, Query
 from sqlalchemy.orm import Session
@@ -20,11 +19,11 @@ router = APIRouter(prefix="/marketplace-import-jobs")
 logger = logging.getLogger(__name__)
 
 
-@router.get("", response_model=List[MarketplaceImportJobResponse])
+@router.get("", response_model=list[MarketplaceImportJobResponse])
 def get_all_marketplace_import_jobs(
-    marketplace: Optional[str] = Query(None),
-    vendor_name: Optional[str] = Query(None),
-    status: Optional[str] = Query(None),
+    marketplace: str | None = Query(None),
+    vendor_name: str | None = Query(None),
+    status: str | None = Query(None),
     skip: int = Query(0, ge=0),
     limit: int = Query(100, ge=1, le=100),
     db: Session = Depends(get_db),