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/__init__.py

@@ -13,9 +13,24 @@ IMPORTANT:
 from fastapi import APIRouter
 
 # Import all sub-routers (JSON API only)
-from . import (analytics, auth, content_pages, customers, dashboard, info,
-               inventory, marketplace, media, notifications, orders, payments,
-               products, profile, settings, team)
+from . import (
+    analytics,
+    auth,
+    content_pages,
+    customers,
+    dashboard,
+    info,
+    inventory,
+    marketplace,
+    media,
+    notifications,
+    orders,
+    payments,
+    products,
+    profile,
+    settings,
+    team,
+)
 
 # Create vendor router
 router = APIRouter()