refactor: remove test/debug

src/utils/duration.ts

@@ -1,15 +0,0 @@
-/**
- * Format a millisecond duration as a human-readable string.
- *  - < 1s:    "450ms"
- *  - < 60s:   "1.23s"
- *  - >= 60s:  "2m 5s"
- */
-export function formatDuration(ms: number): string {
-  if (ms < 0 || !Number.isFinite(ms)) return "0ms";
-  if (ms < 1000) return `${Math.round(ms)}ms`;
-  const seconds = ms / 1000;
-  if (seconds < 60) return `${seconds.toFixed(2)}s`;
-  const minutes = Math.floor(seconds / 60);
-  const remainingSeconds = Math.floor(seconds % 60);
-  return `${minutes}m ${remainingSeconds}s`;
-}