frontend: add lazy server tree and folder items list with synced navigation and local state badges

Co-authored-by: Cursor <cursoragent@cursor.com>

mactfsui/app/lib/utils.ts

@@ -4,3 +4,15 @@ import { twMerge } from "tailwind-merge"
 export function cn(...inputs: ClassValue[]) {
   return twMerge(clsx(inputs))
 }
+
+/**
+ * 把毫秒时间戳格式化为 `YYYY-MM-DD HH:mm`，空值返回占位符。
+ */
+export function formatDateTime(value: number | null | undefined): string {
+  if (value == null || value <= 0) {
+    return "—"
+  }
+  const date = new Date(value)
+  const pad = (input: number) => String(input).padStart(2, "0")
+  return `${date.getFullYear()}-${pad(date.getMonth() + 1)}-${pad(date.getDate())} ${pad(date.getHours())}:${pad(date.getMinutes())}`
+}