fix: 修根因——EventBus加buffer防事件丢失+恢复正确架构

根因：SharedFlow(replay=0,extraBufferCapacity=0)导致emit挂起，
多个collector竞争时事件丢失。之前的补丁越改越乱。

修复：
1. EventBus: extraBufferCapacity=64，emit不再阻塞
2. 恢复正确架构:
   - MainActivity: 监听MQTT type=1→NotificationManager→横幅
   - NotificationManager: 处理后emit NewTaskArrived
   - HomeFragment: 监听NewTaskArrived→红点+统计
3. StatusBarView: 电池位置恢复原位，默认电量-1，主动查询系统电量

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/src/main/java/com/xiaoqu/watch/event/EventBus.kt

@@ -13,7 +13,7 @@ import javax.inject.Singleton
 @Singleton
 class EventBus @Inject constructor() {
 
-    private val _events = MutableSharedFlow<AppEvent>(replay = 0)
+    private val _events = MutableSharedFlow<AppEvent>(replay = 0, extraBufferCapacity = 64)
     val events: SharedFlow<AppEvent> = _events.asSharedFlow()
 
     suspend fun emit(event: AppEvent) {