feat: offline SMS fallback for important notifications

断网时把验证码、来电用短信发到 iPhone：
- ConnectivityMonitor: NetworkCallback 监听在线状态
- CarrierDetector: SIM MCC+MNC 映射移动/联通/电信/广电
- CarrierBalanceQuery: 发免费查询短信拿套餐短信余量，解析回执
- SmsFallbackForwarder: 限频(5min)/余额(≤5挂起)/紧要性检查
- NotificationProcessor 拦截运营商回执(10086/10010/10001/10099)
- 设置页新增短信兜底卡片，首页余额耗尽警告

版本 1.3.0 → 1.4.0

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/build.gradle.kts

@@ -13,8 +13,8 @@ android {
         applicationId = "com.a2i.forwarder"
         minSdk = 34
         targetSdk = 36
-        versionCode = 4
-        versionName = "1.3.0"
+        versionCode = 5
+        versionName = "1.4.0"
     }
 
     signingConfigs {