Panic Fix

internal/pipeline/music.go

@@ -830,7 +830,8 @@ func uniqueMusicName(stem string, used map[string]struct{}) string {
 	}
 	for index := 1; ; index++ {
 		suffix := fmt.Sprintf("_%d", index)
-		candidate := strings.TrimRight(stem[:max(0, maxMusicStemLen-len(suffix))], "_") + suffix
+		prefixLen := min(len(stem), max(0, maxMusicStemLen-len(suffix)))
+		candidate := strings.TrimRight(stem[:prefixLen], "_") + suffix
 		if _, exists := used[candidate]; exists {
 			continue
 		}

internal/pipeline/pipeline_test.go

@@ -2609,6 +2609,17 @@ func TestBuildHAKsConvertsMusicSourcesAndWritesCreditsArtifacts(t *testing.T) {
     }
   ]
 }
+
+func TestUniqueMusicNameHandlesShortStemCollisions(t *testing.T) {
+	used := map[string]struct{}{
+		"mus_wg_mystc": {},
+	}
+
+	got := uniqueMusicName("mus_wg_mystc", used)
+	if got != "mus_wg_mystc_1" {
+		t.Fatalf("unexpected collision result: got %q want %q", got, "mus_wg_mystc_1")
+	}
+}
 `)
 
 	mustWriteFile(t, filepath.Join(root, "assets", "envi", "music", "westgate", "AleandAnecdotes.mp3"), "source-mp3")