feat(background): implement user consent mechanism for auto-start functionality

Add auto-start consent system that requires explicit user permission before enabling background sync services. Users can now choose between silent mode (no auto-start) or background mode (15-minute sync intervals).

- Add consent service with AutoStartMode enum and storage utilities
- Create withRemoveAutoStart Expo plugin to disable Android auto-start defaults
- Integrate consent checks into JPush service, background task manager, and foreground service
- Add auto-start consent UI in notification settings with descriptive dialog
- Update privacy policy with section 8 explaining auto-start scenarios and user controls
- Change default sync mode from BATTERY_SAVER to DISABLED
- Export reinitBackgroundService function for re-initializing after consent changes
- Merge OTA Android and iOS workflows into matrix build
- Add release signing config in withSigning plugin for Android
- Expand .dockerignore with native credential and build artifact exclusions

src/services/notification/jpushService.ts

@@ -112,8 +112,10 @@ class JPushService {
       // Register listeners only once (idempotent guard)
       this._registerListeners();
 
-      // 退后台保持极光长连接，确保推送实时到达
-      this._setBackgroundKeepLongConn(true);
+      // 检查用户是否同意自启动，仅在同意后才保持后台长连接
+      const { isAutoStartAllowed } = await import('../consent/autoStartConsent');
+      const keepLongConn = isAutoStartAllowed();
+      this._setBackgroundKeepLongConn(keepLongConn);
 
       // 初始化 SDK
       JPush!.init({