- Add StealthConfig Pydantic model with all playwright-stealth options
- Add apply_stealth_sync/apply_stealth_async functions for browser context
- Add get_default_stealth_config convenience function
- Add 9 unit tests covering config defaults, stealth application, and disabled mode
- Update conftest.py with stealth_config and mock_browser_context fixtures
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
