Replace hardcoded "no name" fallback with string resource

Use the existing R.string.unknown resource, consistent with how
the subtitle line and other parts of the app handle missing names.

Author: timusus

android/app/src/main/java/com/simplecityapps/shuttle/ui/screens/library/songs/SongListItem.kt

@@ -115,7 +115,7 @@ fun SongListItem(
         ) {
             Text(
                 modifier = Modifier.fillMaxWidth(),
-                text = song.name ?: "no name", // FIXME
+                text = song.name ?: stringResource(R.string.unknown),
                 style = MaterialTheme.typography.bodyMedium,
                 color = MaterialTheme.colorScheme.onBackground,
             )