Implement ErpAuthService with TDD approach:
- Add login(), close(), getSession(), isActive() methods
- Use Playwright chromium with headless:false for debugging
- Manage browser lifecycle and session state
- Handle authentication flow with ERP_LOCATORS
- Add integration tests for login scenarios
- Add unit tests for session management
- Fix dotenv config path in test setup
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
