The date-override path used to look up `image_exif` strictly by
`(library_id, rel_path)` with only the forward-slash form, while
`/image/metadata`'s `get_exif` falls back across libraries and tries
both slash forms. A photo whose row sat under a different library_id
than its filesystem-resolved one — or whose rel_path was stored with
backslashes — rendered fine in the modal but 404'd on save.
`set_manual_date_taken` / `clear_manual_date_taken` now share a
`locate_image_exif_row` helper that mirrors `get_exif`'s union
semantics (scoped lookup first, library-agnostic fallback by rel_path
in both slash forms), then update by primary key so the write hits
exactly the row read. Inner anyhow errors are logged with
`(library_id, rel_path)` so the next failure mode is debuggable.
Handler-side: `resolve_library_param` errors no longer silently fall
back to the primary library (which would have masked the original bug
with a different "row not found"); a malformed library param now
returns 400. New `DbErrorKind::NotFound` lets the handler distinguish
genuine misses (404) from real DB failures (500).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
