Each batch tool now sends an i/n progress ping via ProgressReporter.ReportItem
after processing every item, so a waiting agent doesn't see the MCP client's
300s idle-silence abort while the worker keeps looping. Covers BatchGetTasks,
BatchAddTasks, BatchUpdateTaskStatus, BatchCancelTasks, BatchDeleteTasks,
BatchSetMyDay, and BatchCleanupTaskWorktrees (the slowest of the seven, since
it does git work per task).