- Fix BacktestPageRunResult serialization in jobs.py to correctly access
nested fields from scenario and run_result objects
- Add test_backtest_job.py with comprehensive tests for job execution
- Add conftest_playwright.py with ServerManager that starts FastAPI server
for Playwright tests using uvicorn
- Add test_playwright_server.py with E2E tests using the server fixture
The job serialization bug was causing backtest results to fail silently
because it was trying to access non-existent fields on BacktestPageRunResult.
