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/utils/test_csv_processor.py

@@ -105,9 +105,10 @@ TEST002,Test MarketplaceProduct 2,15.99,TestMarket"""
     @pytest.mark.asyncio
     async def test_process_marketplace_csv_from_url(self, db):
         """Test complete marketplace CSV processing"""
-        with patch.object(
-            self.processor, "download_csv"
-        ) as mock_download, patch.object(self.processor, "parse_csv") as mock_parse:
+        with (
+            patch.object(self.processor, "download_csv") as mock_download,
+            patch.object(self.processor, "parse_csv") as mock_parse,
+        ):
             # Mock successful download and parsing
             mock_download.return_value = "csv_content"
             mock_df = pd.DataFrame(