add datetime utility

src/utils/datetime.ts

@@ -0,0 +1,7 @@
+export function formatTime(iso: string, options?: Intl.DateTimeFormatOptions): string {
+  return new Date(iso).toLocaleTimeString([], {
+    hour: "2-digit",
+    minute: "2-digit",
+    ...options,
+  })
+}