fix: FLAC, Ogg and Opus tracks carry their MusicBrainz recording id from the tag: one reader in library gives the scanner, the backfills and the importer the same ids, and the next scan re-reads the library (#5637)

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

internal/importer/inspect.go

@@ -10,7 +10,6 @@ import (
 	"strings"
 
 	"github.com/dhowden/tag"
-	"github.com/dhowden/tag/mbz"
 
 	"git.fabledsword.com/bvandeusen/minstrel/internal/acoustid"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/library"
@@ -136,15 +135,8 @@ func readFile(ctx context.Context, root, path string) File {
 	f.Title, f.Artist, f.AlbumArtist, f.Album = m.Title(), m.Artist(), m.AlbumArtist(), m.Album()
 	f.Track, _ = m.Track()
 	f.Disc, _ = m.Disc()
-	info := mbz.Extract(m)
-	f.GroupMBID = clean(info.Get(mbz.ReleaseGroup))
-	f.ReleaseMBID = clean(info.Get(mbz.Album))
-	f.RecordingMBID = clean(info.Get(mbz.Recording))
-	if f.RecordingMBID == "" && m.Format() == tag.VORBIS {
-		// Picard's Vorbis key for the recording is MUSICBRAINZ_TRACKID, which
-		// mbz files under its release-track name.
-		f.RecordingMBID = clean(info.Get(mbz.Track))
-	}
+	ids := library.ReadTagMBIDs(m)
+	f.GroupMBID, f.ReleaseMBID, f.RecordingMBID = ids.ReleaseGroup, ids.Release, ids.Recording
 	return f
 }
 
@@ -155,16 +147,6 @@ func rel(root, path string) string {
 	return filepath.Base(path)
 }
 
-// clean takes the first of NUL-separated values: ID3v2.4 multi-values.
-func clean(s string) string {
-	for _, part := range strings.Split(s, "\x00") {
-		if t := strings.TrimSpace(part); t != "" {
-			return t
-		}
-	}
-	return ""
-}
-
 // inspect reads every audio file under root and asks the printer about each.
 // fingerprinted reports whether the printer answered at all.
 func inspect(ctx context.Context, root string, p Printer) (files []File, fingerprinted bool, err error) {