feat: adds hot poll for in-flight CI and workflow status

[wgordon17]

Summary

• Adds a second poll loop (30s default, configurable 10-120s) targeting in-flight workflow runs and pending-check PRs for sub-minute state updates
• Uses individual REST calls for workflow runs and minimal GraphQL nodes() query for PR status, with generation-counter staleness guards and exponential backoff on errors
• Includes 42 new tests covering hot poll coordinator lifecycle, API functions, eviction, caps, error propagation, and backoff