Release 2.5.2

Summary

• Per-Download Audit Trail Modal — every library history row gets an "audit" button that opens a vertical decision-block view of the full download lifecycle (request → source → match → verification → post-process → final placement). new embedded-tags section reads the file live via mutagen and shows every tag actually on disk.
• Write Artist Image (artist.jpg) — new button on artist detail page. writes artist.jpg to the artist's folder so navidrome (which has no artist-image API) gets a real artist photo instead of the album-art fallback. plex / jellyfin pick it up too. respects existing artist.jpg files.
• Discography 50-cap fix — download discography no longer truncates prolific artists. bumped the limit from 50 → 200 so deezer / itunes / discogs / hydrabase users see full catalogues. spotify behavior unchanged.
• $albumtype template fix for non-spotify sources — discographies downloaded from deezer / tidal / musicbrainz no longer dump every release under Album/. legacy album-info builder now checks record_type / type / primary-type alongside album_type and normalizes through a shared helper. EPs and singles route to the right folder.
• Search source picker default fix — enhanced + global search no longer silently default to spotify when the user's primary metadata source is deezer / itunes / discogs / hydrabase. backend was returning metadata_source as a dict, frontend was reading it as a string, validation guard never fired.
• Download Missing Modal: tracklist polish — visual tune-up (column layout untouched). hairline row dividers, accent gradient + edge bar on hover, monospace track numbers / duration, status text picks up colored dot indicators with soft halos, pulses while in-flight.