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/middleware/test_theme_context.py

@@ -16,9 +16,11 @@ from unittest.mock import AsyncMock, MagicMock, Mock, patch
 import pytest
 from fastapi import Request
 
-from middleware.theme_context import (ThemeContextManager,
-                                      ThemeContextMiddleware,
-                                      get_current_theme)
+from middleware.theme_context import (
+    ThemeContextManager,
+    ThemeContextMiddleware,
+    get_current_theme,
+)
 
 
 @pytest.mark.unit
@@ -144,12 +146,12 @@ class TestThemeContextMiddleware:
         mock_db = MagicMock()
         mock_theme = {"theme_name": "test_theme"}
 
-        with patch(
-            "middleware.theme_context.get_db", return_value=iter([mock_db])
-        ), patch.object(
-            ThemeContextManager, "get_vendor_theme", return_value=mock_theme
+        with (
+            patch("middleware.theme_context.get_db", return_value=iter([mock_db])),
+            patch.object(
+                ThemeContextManager, "get_vendor_theme", return_value=mock_theme
+            ),
         ):
-
             await middleware.dispatch(request, call_next)
 
         assert request.state.theme == mock_theme
@@ -184,12 +186,14 @@ class TestThemeContextMiddleware:
 
         mock_db = MagicMock()
 
-        with patch(
-            "middleware.theme_context.get_db", return_value=iter([mock_db])
-        ), patch.object(
-            ThemeContextManager, "get_vendor_theme", side_effect=Exception("DB Error")
+        with (
+            patch("middleware.theme_context.get_db", return_value=iter([mock_db])),
+            patch.object(
+                ThemeContextManager,
+                "get_vendor_theme",
+                side_effect=Exception("DB Error"),
+            ),
         ):
-
             await middleware.dispatch(request, call_next)
 
         # Should fallback to default theme