build(config): update bundle identifier and add signing plugin

feat(notification): improve JPush integration and message sync reliability

- Update iOS bundle identifier to `cn.qczlit.weiyou`
- Add `withSigning` Expo plugin
- Enhance `withJPush` plugin with improved Swift AppDelegate injection logic
- Update JPush default channel to `developer-default`
- Optimize `MessageSyncService` to prevent race conditions in unread count updates
- Implement promise deduplication for `fetchUnreadCount` to prevent redundant network requests
- Add `setConversationsWithUnread` to `useMessageStore` for atomic state updates of conversations and unread counts

app.json

@@ -25,7 +25,7 @@
         ],
         "ITSAppUsesNonExemptEncryption": false
       },
-      "bundleIdentifier": "cn.qczlit.withyou"
+      "bundleIdentifier": "cn.qczlit.weiyou"
     },
     "android": {
       "adaptiveIcon": {
@@ -66,6 +66,7 @@
       "favicon": "./assets/favicon.png"
     },
     "plugins": [
+      "./plugins/withSigning",
       "./plugins/withMainActivityConfigChange",
       [
         "./plugins/withForegroundService",