feat(android): libbox 隧道重写对接真实 1.13.12 API,APK 编译通过(Task 5)

原生层照 PoC 旧/想象 API 写,与真实 sing-box 1.13.12 libbox 差距是架构级:

- 包名 libbox(非 go.libbox);无 BoxService,改 Libbox.setup + CommandServer 模型

- PangolinVpnService 重写:实现完整 PlatformInterface(15法)+CommandServerHandler

- 新增 DefaultNetworkMonitor(上报默认接口,缺则报 no available network)

- openTun 适配真实 TunOptions(RoutePrefixIterator/getMTU/StringBox DNS)

- 统计/切节点经 CommandClient(uplinkTotal/selectOutbound);MainActivity 接线

构建环境矩阵打通:Gradle 8.7(Java21)+声明式插件迁移+AGP 8.6+Kotlin 2.2.0+占位图标

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/android/gradle.properties

@@ -1,3 +1,7 @@
 org.gradle.jvmargs=-Xmx4G -XX:MaxMetaspaceSize=2G -XX:+HeapDumpOnOutOfMemoryError
 android.useAndroidX=true
 android.enableJetifier=true
+# This builtInKotlin flag was added automatically by Flutter migrator
+android.builtInKotlin=false
+# This newDsl flag was added automatically by Flutter migrator
+android.newDsl=false