- Add fetchThrottled utility to GitHubClient with 429 retry handling and exponential backoff
- Implement POST /api/github/batch-import endpoint for bulk GitHub resource imports
- Add frontend API client function for batch import operations
- Add comprehensive tests for throttled requests and batch import endpoint
- Add retryAfter field to batch import result types for rate limit handling
- Clean up unfinished UsageIndicator component and worktree retry cleanup code
- Add changeset documenting the new batch GitHub import feature
