• This issue is blocking
• This issue is causing unreasonable pain

As noted here: https://developercommunity.visualstudio.com/t/ADO-pipeline-timeouts-dont-cancel-the-s/1371617?space=21&entry=myfeedback&viewtype=all, it seems that the automated cancellation feature I built doesn't run as often as we'd expect because it's far more common for a build to time out than be cancelled via push. Perhaps ADO will fix this.

In the mean time, we could make it simpler to cancel jobs in this scenario by:

• Introduce a build task that, given a cancellation token (could use API Access token too but not necessary since all jobs produce unique cancellation tokens), calls the Helix API for job cancellation.
• Add ADO logging commands to emit all started jobs and their cancellation tokens for consumption by later steps