feat(subsonic)!: drop support for guessed artist covers in filesystem

it doesn't make sense with multi-artist support anymore

gonic will use lastfm or an album cover instead

Release-As: 0.16.0

db/migrations.go

@@ -57,6 +57,7 @@ func (db *DB) Migrate(ctx MigrationContext) error {
 		construct(ctx, "202304221528", migratePlaylistsToM3U),
 		construct(ctx, "202305301718", migratePlayCountToLength),
 		construct(ctx, "202307281628", migrateAlbumArtistsMany2Many),
+		construct(ctx, "202309070009", migrateDeleteArtistCoverField),
 	}
 
 	return gormigrate.
@@ -589,3 +590,18 @@ func migrateAlbumArtistsMany2Many(tx *gorm.DB, _ MigrationContext) error {
 
 	return nil
 }
+
+func migrateDeleteArtistCoverField(tx *gorm.DB, _ MigrationContext) error {
+	if !tx.Dialect().HasColumn("artists", "cover") {
+		return nil
+	}
+
+	step := tx.Exec(`
+		ALTER TABLE artists DROP COLUMN cover;
+	`)
+	if err := step.Error; err != nil {
+		return fmt.Errorf("step drop: %w", err)
+	}
+
+	return nil
+}