ci: Fleet status runs only for a comment that can change a status

[askalf]

Summary

• Fleet status on comments. Every comment on a PR started a Fleet status run on the exec runner, though scripts/fleet-status.mjs reads only ## Verification at <sha> comments. Preview bots' comments started dozens a day (amnesia 33, plumbline 20 in 48 hours). issue_comment now runs the job only when the comment starts with ## Verification at, or did before an edit (github.event.changes.body.from). A deleted verification comment still runs it, because the event carries the deleted body.
• fleet-status-self-test no longer runs for a PR that changes only .github/workflows/redline.yml or redline-fix.yml, which is every Redline pin bump (18 to 23 self-test runs per repo in 48 hours). It is not a required check here, and any other workflow change, the script or its test still runs it.

Tests

scripts/fleet-status.test.mjs: 220 pass, 0 fail. The if: evaluator learns startsWith, case-insensitive like GitHub's. The new checks cover:

• a verification comment on a PR runs the job, and one on an issue does not;
• a preview bot's comment, a person's comment and an empty one do not;
• an edit away from a verification comment, and a deleted one, still run it.

[sprayberry-redline]

Verdict: request changes. The comment filter preserves verification updates, including edits away from the heading and deletions, and the tests exercise those cases. The new workflow comment needs revision to describe the job condition rather than past run volume.

1. Blocking: .github/workflows/fleet-status.yml:44

# And only a verification comment changes a status, so no other comment starts a run (preview
# bots' comments started dozens a day); an edit away from one, or its deletion, still does.

The parenthetical narrates past run volume rather than explaining the condition. The comment also says unrelated comments do not start a run, but issue_comment still triggers the workflow; the job condition only skips the status job.

Suggested fix:

Replace this with a comment explaining that the status job runs only when the current or previous comment body starts with the verification heading, including deleted comments.

rule:reads-as-generated

[sprayberry-redline]

Verdict: approve. The comment filter preserves updates for verification comments, edits away from verification, and deletions, with tests covering those cases and unrelated comments. The self-test path exclusions are limited to the two Redline workflows and leave other workflow and script changes covered.