fix(source-control): stop one workflow-editing PR from marking both review lanes failing in review-venue #8867

Refs: #7576

Problem

/source-control:pull-request review-venue decides whether a pull request's AI reviews run in CI or locally. It reads each lane's newest completed pull_request run across the whole repository that is not skipped or cancelled (plugins/source-control/skills/pull-request/scripts/review-venue.sh:110). One pull request that edits workflows ends both review lanes in their designed red. That one run then marks both lanes local failing for every other pull request, so ready runs local stand-in reviews it does not need.

Observed 2026-10-21 13:40Z: runs 39610040287 and 39610040502 (both #8800, "ci: repin ci-workflows to v0.58.0") made both lanes read local failing while the lanes were healthy.

Desired behavior

A lane reads failing only when its failures say something about the lane, not about one pull request. Options, to settle in the fix:

• skip runs whose conclusion is the designed skipped-validation red for a workflow-editing pull request (it needs a signal the run exposes, such as a job name or an annotation);
• or judge health over the newest N runs, so one red run among greens stays healthy;
• or read the lane's run for the pull request at hand first.

A real lane outage, where several recent runs fail, must still read failing.

Known calls

• Origin: found while taking fix(source-control): apply the stricter of the base and main merge config in pr-merge #8860 through ready; GitHub Support identified the runs. Ours.
• Cost of the bug: extra local reviews, never a skipped review. It fails toward more review.