feat(t03): improve performance and UX

- add category/tag caching and optimistic updates

- add stats dashboard aggregation and batched tracking

- add undo delete snackbar and group read-only view mode

- improve app-ready timeout handling and refresh guards

client/src/utils/tracker.ts

@@ -14,8 +14,8 @@ interface TrackEvent {
 /** 上报队列（批量上报，减少请求） */
 let eventQueue: TrackEvent[] = []
 let flushTimer: number | null = null
-const FLUSH_INTERVAL = 5000 // 5秒上报一次
-const MAX_QUEUE_SIZE = 20
+const FLUSH_INTERVAL = 500 // 500ms 攒批
+const MAX_QUEUE_SIZE = 10   // 10 条立即发送
 
 /** 获取当前页面路径 */
 function getCurrentPage(): string {