🚑 fix: runner: Report staging left at the cancellation deadline #473

The public host can reach its cancellation deadline while the extension is still deleting a large private staging tree. On mini, a 100,000-file tree remained after both SIGINT and SIGTERM. The answer kept the signal error and exit, but omitted the handler's stage field, so it did not identify the remaining tree.

This is the measured larger-tree follow-up requested during #468, outside the batch. Chef explicitly treats it as nonblocking for #468's 20,000-file acceptance. Do not extend or remove the outer bound as an untested workaround.

Observed on mini (Darwin), head 66a7ed509d8f7cb1e72ddad020eeb9ed6e2e18ed, build ncly v0.26.1-0.20261104022449-66a7ed509d8f, through the real public ncly hello staged path with a resistant worker and detached grandchild. The nominal reservation is the final 2 s of a 15 s cancellation budget.

The handler never wrote cleanup.json, so there is no completed deletion or cleanup duration to quote. The measurement records the incomplete cleanup at CLI exit, before harness cleanup. Receipt ok:true means both observations were collected and the disposable remote folder was cleaned. The observer correctly records observations_complete:true, passed:false.

The separate strict gate passed ten SIGINT plus ten SIGTERM calls with 20,000 files. Maximum deletion was 811 ms, maximum cleanup 912 ms, and minimum reservation margin 1088 ms. A separate 100-file calibration passed both signals with deletion 7 ms and cleanup 108 ms.

Complete strict receipt and twenty-run quote. Complete calibration and 100,000-file receipts, exact commands, observer diff and quotes. These comments preserve the source and commands when the temporary folders are removed. The scratch observer snapshots state before the canonical guards and continues to the second signal after a failure. It changes no product file, fixture or cancellation budget.

The actual signal answers were:

{"ok":false,"contract_version":1,"errors":[{"code":"INTERRUPTED","message":"Stopped by Ctrl-C. Finished work is kept.","hint":"Check the results before you run anything again."}]}
{"ok":false,"contract_version":1,"errors":[{"code":"TERMINATED","message":"Stopped by SIGTERM. Finished work is kept.","hint":"Check the results before you run anything again."}]}

Next: decide how bounded cancellation reports and recovers an incomplete private staging cleanup. Keep the outer bound and descendant-stop behavior. A repair must cover both signals with a real public host and preserve input and existing output. Retain the passing 20,000-file and cooperative/direct controls. Avoid a video-convert-specific exception.

by GPT-6.1-Sol via Codex