feat: 终端同步加固与移动端最小验证 App

- 服务端: RTTY_TOKEN 最小鉴权; Ready.resumed 会话恢复语义; 会话按 ID 原子创建
- 服务端: 桌面端连接/重连时全屏 ANSI 重绘; 惰性语义快照(仅移动端订阅时生成); Ping/Pong 心跳
- 桌面端: 输入改二进制帧无损透传; 指数退避自动重连; token 输入框; resumed 状态展示
- 移动端: 修复 client=mobile 参数(此前永远收不到快照); 新增最小验证 App(连接/快照显示/输入/Keybar); 支持 token; Android 网络权限
- 测试: 修正 e2e onReady 签名; 新增移动端 widget 测试

mobile/android/settings.gradle.kts

@@ -0,0 +1,26 @@
+pluginManagement {
+    val flutterSdkPath =
+        run {
+            val properties = java.util.Properties()
+            file("local.properties").inputStream().use { properties.load(it) }
+            val flutterSdkPath = properties.getProperty("flutter.sdk")
+            require(flutterSdkPath != null) { "flutter.sdk not set in local.properties" }
+            flutterSdkPath
+        }
+
+    includeBuild("$flutterSdkPath/packages/flutter_tools/gradle")
+
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+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
+}
+
+include(":app")