feat(mobile,deploy): 接入安卓极光与华为通道并准备公网部署配置

客户端默认指向 jxd.jinniu.ink 的 HTTPS/WSS；登录后把 OpenIM userID 设为极光 alias。
华为 agconnect-services.json 不伪造、不入库。Master Secret 只从服务器文件注入。

Co-authored-by: multica-agent <github@multica.ai>

mobile/android/settings.gradle.kts

@@ -15,6 +15,7 @@ pluginManagement {
         maven("https://maven.aliyun.com/repository/google")
         maven("https://maven.aliyun.com/repository/central")
         maven("https://maven.aliyun.com/repository/gradle-plugin")
+        maven("https://developer.huawei.com/repo/")
         google()
         mavenCentral()
         gradlePluginPortal()
@@ -25,6 +26,7 @@ plugins {
     id("dev.flutter.flutter-plugin-loader") version "1.0.0"
     id("com.android.application") version "9.0.1" apply false
     id("org.jetbrains.kotlin.android") version "2.3.20" apply false
+    id("com.huawei.agconnect") version "1.9.1.301" apply false
 }
 
 include(":app")