feat: import with verification, and a Wanted view of its own (M502 #5522)

A finished download is checked against MusicBrainz before anything is
filed: the files are paired with an edition's tracks by position or path,
and AcoustID, tag ids, lengths and titles say whether it is the album.
What is the album is copied into the library as
Artist/Album (Year)/Artist - Album - NN - Title, tagged with Picard's
MusicBrainz ids, and scanned; the download keeps seeding. What is not is
refused: set aside, removed from the client, and the album searched for
again. A download the check cannot settle waits for a person, who imports
it anyway or refuses it. Tracks the library already holds are skipped.

The wanted list leaves Admin for a top-level Wanted view, admin-only and
web-only, with tabs for Wanted, Activity (downloads and their imports,
the ones needing a person first), Missing files, Held, Following (with the
release-type profiles, moved off Integrations) and Blocked. The search
settings gain "File new music into" when the library has several folders.

The search pass logs why each failed search failed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -40,11 +40,13 @@ services:
     ports: ['4533:4533']
     volumes:
       # Your music library. Point ./music at wherever your audio files
-      # live. Writable, because Minstrel deletes a file when an admin asks
-      # it to (for example, quarantine's "Delete file"). It never moves,
-      # renames or retags anything. The container runs as uid 1000, so that
-      # user needs write access to the folders. Mount it :ro to forbid even
-      # deletes: those actions then refuse, say why, and delete nothing.
+      # live. Writable, because Minstrel files the albums it downloads into
+      # it (as Artist/Album (Year)/..., tagged with MusicBrainz ids) and
+      # deletes a file when an admin asks it to (for example, quarantine's
+      # "Delete file"). Files already there are never moved, renamed or
+      # retagged. The container runs as uid 1000, so that user needs write
+      # access to the folders. Mount it :ro to forbid writes: those actions
+      # then refuse, say why, and change nothing.
       - ./music:/music
       # Generated data: playlist cover collages, artist art, caches.
       # The path must match MINSTREL_STORAGE_DATA_DIR, which the image