Round 2 of extensive_testing on 2e738a8 found the fix only closed the
race at queue time. state.notice is shared with a third writer:
_recordSegment unconditionally blanked it on every successful render
(state.notice = "" whenever recordedSceneIds.length), which exists to
retire ITS OWN "N saved renders no longer on disk" message once a
regen fixes it -- but fires on every successful run regardless, so it
silently ate the reference-unwired notice the instant the very run it
described finished. A person who wasn't watching the screen during
generation would find the notice gone by the time they looked back.
Added _noticeIsStaleRenders, tracking which case currently owns
state.notice, so _recordSegment only clears its own message.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
