The PhotoExportMenu's TXT format advertises "Simple text list for Lightroom
search" but emitted newline-separated filenames WITH `.jpg`. Lightroom's
filename search wants a comma-separated one-liner, and the gallery JPEGs may
correspond to RAW files in the catalog — so the search has to match on the
stem only.
The frontend now passes `separator: 'comma'` + `include_extension: false` for
the TXT format specifically. The backend gains an `include_extension` option
(defaulting to true so direct API consumers don't break), and the comma case
joins without a trailing space (the form Lightroom expects). Unit test pins
the Lightroom-mode output AND the backward-compatible default for any direct
API caller.
CSV / XMP / JSON exports are unchanged.
Paul Nothaft
a239fec9d7