A write, an undo or an accepted write decided into the ledger waited out the
worker's 30 s idle sleep. Mirror::journalled now says whether it added a line,
and memoryd wakes the worker when it did. The Wake lock is a leaf, taken under
the index lock as before.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
