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: 180 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 refreshes for verification comments, including edits away from the heading and deletions. The new workflow comment needs to describe the condition rather than narrate 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 records past preview-bot run volume in a code comment. That patch history does not explain the condition or its edge cases.

Suggested fix:

Remove the run-volume parenthetical. Keep a short explanation that verification comments, edits away from them, and deletions require a status refresh.

rule:reads-as-generated

[sprayberry-redline]

Verdict: approve. The comment filter preserves updates for verification comments, edits away from them, and deletions while skipping unrelated comments. The tests exercise the workflow condition directly, and the self-test path exclusions leave other workflow and script changes eligible.