- Add batch status API types (BatchStatusRequest, BatchStatusResponse, etc.)
- Add batch GitHub client wrappers for efficient PR/issue status fetching
- Create useBatchBadgeFetch hook for coordinated dashboard fetching
- Update Board component to batch fetch badge statuses on mount
- Update TaskCard to merge batch, WebSocket, and task data with freshness comparison
- Add batch status REST endpoint at POST /api/tasks/batch/status