Two related fixes that the old delete flow was missing:
1. delete_from_library now accepts an optional `db` parameter which
it forwards to find_library_files. Without `db`, only digit-stem
files match (the old behavior — preserved as a fallback). With
`db`, templated filenames stored in library_meta also match,
so post-refactor saves like 12345_hatsune_miku.jpg get unlinked
too. Without this fix, "Unsave from Library" on a templated
save was a silent no-op.
2. Always cleans up the library_meta row when called with `db`, not
just when files were unlinked. Two cases this matters for:
a. Files were on disk and unlinked → meta is now stale.
b. Files were already gone but the meta lingered (orphan from
a previous broken delete) → user asked to "unsave," meta
should reflect that.
This is the missing half of the cleanup that left some libraries
with pathologically more meta rows than actual files.