refactor(app): App-per-screen navigation, remove menu_level entirely

Splits the ad-hoc menu_level state machine into standalone Apps with a
uniform parent/child exit convention (long-press CONFIRM -> parent):
clock_app renamed to home_app (boot-default), new set_clock_app
extracted from home_app's time-edit mode, new ipc_bind_app extracted
from menu_app's old level-2 screen, and the sensor-type selection step
merged into pair_app as its new initial state. menu_app now only holds
the 4-item top-level list (language toggle inline). Also makes both
menu_app and pair_app's up/down navigation cyclic (wraps at both ends).

App/config.h

@@ -108,12 +108,14 @@ typedef enum {
 
 /* ====== 应用程序 ID 枚举 ====== */
 typedef enum {
-    APP_ID_CLOCK,  // 待机时钟应用程序 (首屏)
-    APP_ID_MENU,   // 系统设置与操作主菜单应用程序
-    APP_ID_PAIR,   // 无线传感器对码学习应用程序
-    APP_ID_ALARM,  // 报警接收与波形反馈应用程序
-    APP_ID_SOS,    // 紧急呼救与无线发射应用程序
-    APP_ID_MAX     // 应用程序最大数量上限，用于数组大小
+    APP_ID_HOME,      // 待机时钟主页应用程序 (开机默认首屏)
+    APP_ID_MENU,      // 系统设置主菜单应用程序 (顶层 4 项列表)
+    APP_ID_SET_CLOCK, // 时间设置应用程序 (menu_app 子应用)
+    APP_ID_PAIR,      // 无线传感器对码学习应用程序 (menu_app 子应用)
+    APP_ID_IPC_BIND,  // 摄像头一键绑定应用程序 (menu_app 子应用)
+    APP_ID_ALARM,     // 报警接收与波形反馈应用程序
+    APP_ID_SOS,       // 紧急呼救与无线发射应用程序
+    APP_ID_MAX        // 应用程序最大数量上限，用于数组大小
 } AppID;
 
 /* ====== 应用程序类型枚举 ====== */