Stop reporting cancelled runs as failures

[tschm]

A run that was stopped by hand, or killed by a concurrency group when a newer push superseded it, carries no verdict about the branch — and stale means it never really ran. Both were counted as red, so a repo went red for the sole reason that somebody cancelled a job.

What changes

• Default branch. Cancelled and stale runs are skipped when picking each workflow's latest run, so a workflow keeps showing its last real verdict. The targeted per-workflow fetch now asks for 5 runs instead of 1, because the newest one may be the cancelled one and the API has no "conclusive only" filter.
• Nothing to judge stays absent. A workflow whose only runs are cancelled is left out of the exposition entirely, rather than reported red — the same way a workflow that never ran is. Likewise jq_ci_last_run* is not emitted for a repo whose only run was cancelled.
• Pull requests follow the same rule. Only failure counts toward jq_open_pull_requests_failing. The PR table still shows cancelled in its checks column, so the information isn't lost — it just doesn't read as red.
• Dashboards. Both boards drop cancelled from the failing-PR panel queries.

Testing

pytest — 51 passed. Six new tests cover the fallback to the last conclusive run, the absent-not-red case on both layers, the multi-run direct fetch, and the PR count.

🤖 Generated with Claude Code