fix: correct all async route status code assertions (POST=202, GET poll=200)

fix: correct expected status code in test_async_analyze_returns_job_id to 202

fix: set mock_result.status and correct status code assertion in poll success test

fix: correct expected status code in job poll test to 200

fix

fix: correct expected status code in async job submission test to 202

test(integration): add end-to-end test for async job submission and poll-to-completion cycle

feat: add integration tests, GitHub API mocking, and Locust load tests