* Keep temp-directory assets visible while their files exist
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.
* Cover the unhashed temp asset in the reconciliation tests
The existing temp tests all registered hashed assets, so they never
exercised the path an unhashed asset takes when its file is gone: the
orphaned rows are removed rather than kept as missing, exactly as under
any other root.
tag_type was always "user" in practice — no code path ever set it to anything
else (no system/seeded classification was wired up) and nothing queried it. The
column, its ix_tags_tag_type index, and the TagUsage.type API field were dead
weight, so they're removed. Adds alembic migration 0004 to drop the column and
index.
Verified: asset-seeder tests pass; migration applies cleanly on a fresh SQLite
(tags retains only name; tag_type column + index dropped).
Co-authored-by: guill <jacob.e.segal@gmail.com>