Abort or interrupt a running run

I'd like to be able to cancel a run that's already claimed, started, or in progress. Sometimes something goes wrong and you know you want to stop it right away, but a long run might take 45 minutes to complete or, worse yet, a crashed worker might not lead to your run being marked as "lost" for 60 minutes.

Proposal

1. Click into a running run, and you should find a "cancel" button.
2. Select a bunch of work orders from history in state "running" and you should be able to cancel any associated runs for those work orders (in the same way you can cancel pending runs in #1622 )
3. Doing so should send a new event to the worker, telling it to abort, cease & desist, etc., etc.
4. The worker should then send back some tidying up data - last logs, final state with a cancellation reason, etc.
5. Basically, we don't want to shut the door from the lightning side... we want to tell the worker to stop and clean up immediately.

Start by reviewing the existing pending-run cancellation flow referenced in #1622, then trace how running work orders and worker events are handled. Done means the UI can cancel running runs individually or in bulk, the worker receives an abort event, and cancellation returns final state, a reason, and cleanup logs.