refactor(event): replace global 60s inactivity timer with per-second tick event

Adds KEY_EVENT_SECOND_TICK, generated once per real second from
Clock_IncMS() via a new second_tick_flag and pushed through the normal
event queue, so every foreground App's onEvent() receives it and
decides independently whether to act. Removes the old global
inactivity_timer (60s sleep from anywhere) entirely. HomeApp now
accumulates its own idle-second counter and sleeps after 10s idle
specifically while on the home screen; MenuApp's existing 10s
auto-close is converted from onRun() polling to the same tick+reset
pattern for consistency. Any non-tick key event resets each app's own
counter to 0.

App/clock.c

@@ -6,6 +6,7 @@ u8 current_hour = 10;                     // 系统软时钟：小时 (默认初
 u8 current_min = 35;                      // 系统软时钟：分钟 (默认初始化为 35 分)
 u8 current_sec = 0;                       // 系统软时钟：秒
 volatile u8 clock_updated = 0;            // 分钟跳变标志位，置位后用于驱动 UI 刷新时间显示
+volatile bit second_tick_flag = 0;        // 整秒滴答标志位，每次秒进位置 1，由主循环转换为 KEY_EVENT_SECOND_TICK 事件
 
 // 毫秒计数器 (Timer1 每 1ms 累加)
 static u16 ms_cnt = 0;
@@ -20,6 +21,7 @@ void Clock_IncMS(void)
     if (ms_cnt >= 1000) {
         ms_cnt = 0; // 1秒时间到
         current_sec++;
+        second_tick_flag = 1; // 整秒滴答，通知主循环生成 KEY_EVENT_SECOND_TICK 事件
         if (current_sec >= 60) {
             current_sec = 0; // 1分钟时间到
             current_min++;