style: fix black code formatting

- Add missing blank line after mypy disable comment
- Ensure all files pass black formatting checks
- Fix CI/CD workflow formatting requirements

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: maxprilutskiy

src/lingodotdev/engine.py

@@ -1,6 +1,7 @@
 """
 LingoDotDevEngine implementation for Python SDK
 """
+
 # mypy: disable-error-code=unreachable
 
 from typing import Any, Callable, Dict, List, Optional