fix(cli): stop waiting for the cloud's file check when the caller aborts - #7361

Approving at 2ad3a7ed. No blockers.

• The fix is correct. sleep(ms, signal) resolves early on abort, and the new signal?.aborted check right after it throws "Stopped waiting for the cloud to finish checking the uploaded file." with cause: signal.reason. uploadAssetViaDirectUpload now passes opts.signal through. The wait is cut short at the next sleep, not after the full 10-minute budget.
• The "fails without the fix" claim holds. I ran it locally. With the abort check removed and sleep back to no signal, stops waiting when the caller aborts times out (1 failed, 4 passed in uploadComplete.test.ts). With the fix restored, vitest run src/cloud/upload* passes 25 of 25.
• The test rename is accurate. The 20×409 test polls for about 88 s, so "more than a minute" is right.
• CI on this head: CI, CodeQL, regression, preview-regression, PR captures, Player perf and Comments are all green. Windows render verification was still running and doesn't touch this code.

Non-blocking nits:

1. sleep adds its abort listener only when the signal fires later. If Ctrl-C lands while completeAssetUpload is in flight, the next sleep still waits its full poll (at most 5 s) before the check throws. A if (signal?.aborted) throw … before the sleep, or an early resolve in sleep when the signal is already aborted, would make it instant.
2. Each sleep leaves a { once: true } listener on the signal when the timer wins. Over a 10-minute wait that's about 120 dead closures. They're harmless, but sleep could remove its listener in the timeout path.