Pack now writes <Name>.cache, or <Name>.cache.1, .2, ... if that file
already exists (replaces the fixed .cache.new name). Unpack writes each
target folder under ARCANE_DUMP the same way, e.g. COBJECTS.1. The
output folder is created only after the cache loads, so a missing cache
does not leave an empty numbered folder.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>