#512 ci: cancel superseded pull request runs in the four path-filtered workflows

A new push to a pull request now cancels that pull request's older run of the same workflow, for the four workflows that run on pull requests: contained-source, daemon-lifecycle, highlight-lifecycle and kernel-stamp. All four trigger only on pull requests, so no run on fork/consolidated is affected.

The group key is the workflow name plus the pull request number. Each workflow has its own name, so they do not cancel each other.

In the last 30 days these workflows ran 141 times on pull requests. 24 of those were still running when a newer run started on the same branch, about 145 minutes of runner time, all of it from daemon-lifecycle. That figure is estimated from run timestamps. The workflows use path filters, so a push that matches no path starts no replacement run and the older run finishes as before.

README rows checked: none are affected, since no user-visible feature, number or config key changes. This pull request touches the workflow files, which are in their own path lists, so all four run on it.

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Summary by cubic

Adds concurrency cancellation to the four PR-only workflows (contained-source, daemon-lifecycle, highlight-lifecycle, kernel-stamp) so a new push to a PR cancels the older run of the same workflow. In the last 30 days, 24 of 141 PR runs were superseded, wasting roughly 145 minutes of runner time.

• The group key is the workflow name plus the PR number, so the four workflows don't cancel each other.
• Runs on fork/consolidated are unaffected since these workflows only trigger on pull requests.
• Path filters still apply: a push that matches no path won't start a replacement run, so the older run finishes as before.

Summary by CodeRabbit

• Chores
  • Updated pull request checks to cancel an earlier in-progress run when a newer run starts for the same workflow and pull request.
  • This prevents overlapping runs and ensures the latest changes are checked.