Date sorting previously used a DB-level query that acted as an inner join,
silently dropping files with no image_exif row. Replace it with the existing
in-memory sort which already falls back to filename-extracted and filesystem
dates, so all files appear in sorted results.
Also removes the now-unused get_files_sorted_by_date trait method and its
SqliteExifDao implementation and test mock.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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