feat: the library's albums go on the wanted list as held, once; after that the list is the truth (M502 #5567)

A one-time job in the wanted worker lists every album in the library as a
held want, one per release group, with a record that it happened
(acquisition_settings.library_listed_at). Albums whose tags name only a
release are named on MusicBrainz first, 120 a pass; what nothing names is
counted and shown on the Held tab.

Re-acquisition now wants back only albums on the list. Taking a held album
off the list leaves its files, and it is never fetched back; albums put in
the library folder by hand afterwards are not added.

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

internal/dbtest/reset.go

@@ -185,10 +185,13 @@ func ResetDB(t *testing.T, pool *pgxpool.Pool) {
 		t.Fatalf("dbtest.ResetDB reset release-type profiles: %v", err)
 	}
 	// Search and grab settings (M502 #5521), a singleton reset the same way.
+	// The library listing (#5567) reads as done, so a test's albums are not
+	// put on the wanted list behind its back; its own tests clear it.
 	if _, err := pool.Exec(ctx, `
 		UPDATE acquisition_settings
 		   SET auto_grab = DEFAULT, search_interval_hours = DEFAULT, allowed_qualities = DEFAULT, import_root = DEFAULT,
 		       seed_ratio = DEFAULT, seed_days = DEFAULT, stall_hours = DEFAULT,
+		       library_listing_started_at = now(), library_listed_at = now(), library_unlisted = 0,
 		       last_pass_at = NULL, last_pass = DEFAULT, updated_at = DEFAULT`,
 	); err != nil {
 		t.Fatalf("dbtest.ResetDB reset acquisition settings: %v", err)