Prevented the durable queue from claiming a queued event while another event with the same issue key is still running, so duplicate worker instances cannot resume the same RpcClient session concurrently.
Added regression coverage for blocked same-issue events and for skipping blocked queue heads without stalling unrelated issues.
Fixes#1840
- Added `review_pr` task that checks out PR head in a detached worktree, classifies rank/type/area, and posts a batched GitHub review as `event=COMMENT`.
- Added four new host tools: `fetch_pr`, `classify_pr`, `pr_review_comment`, and `submit_pr_review`; review tools self-gate on `review_mode`, push/open-PR tools refuse when `review_mode` is set.
- Added sqlite staging table `pr_review_comments` with `stage_review_comment`, `list_staged_review_comments`, and `clear_staged_review_comments` DAOs.
- Routed `pull_request.opened/reopened/ready_for_review` to `review_pr` and extended `pull_request.closed` cleanup to any tracked PR regardless of author.
oldschoola