Assets written to the temp directory were flagged as missing and dropped
from GET /api/assets, even with the file sitting on disk. One list of
directories was answering two different questions -- where the scanner
looks for new files, and which files ComfyUI considers its own -- and
temp belongs only in the second, so every temp reference was disowned by
the prune that runs at startup and on POST /api/assets/prune.
Ownership now covers temp. Discovery still does not: the temp directory
is wiped before the scan runs, and assets written there are already
registered with a hash, mime type and dimensions, so walking it would
find nothing. Temp references are instead reconciled against the
filesystem directly, so a temp file that really is gone is still retired
rather than lingering as a broken entry.
get_prefixes_for_root becomes get_scan_prefixes_for_root so the two
questions are told apart by name rather than by comment.
