Splicing a JSON-authored INSERT target by name previously resolved
through the same shared CUTSCENE_LOADED_ITEMS/POOL buffer as whatever
outer cutscene was currently running, so loading it would clobber the
outer cutscene's own items mid-playback - that's why it was reverted.
Gives INSERT its own smaller CUTSCENE_INSERT_ITEMS/POOL buffer and lets
the cutscene asset loader be told which buffer set to parse into, so an
INSERT's dynamic load no longer stomps the running cutscene.
Co-Authored-By: Claude Sonnet 5 <[email protected]>