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/lib/src/theme.dart

@@ -0,0 +1,59 @@
+import 'package:flutter/material.dart';
+
+/// Rtty 移动端主题。
+///
+/// 设计方向：现代终端卡片美学。深靛蓝底 + 霓虹青绿强调色，
+/// 用卡片承载命令与输出，强调可读性与触控友好。
+class RttyMobileTheme {
+  RttyMobileTheme._();
+
+  static const Color background = Color(0xFF0D1117); // 深靛黑
+  static const Color surface = Color(0xFF161C26); // 卡片底
+  static const Color surfaceAlt = Color(0xFF1C2430); // 输入区
+  static const Color border = Color(0xFF2A3442);
+  static const Color primary = Color(0xFF3DDB93); // 霓虹青绿
+  static const Color primaryDim = Color(0xFF176C4B);
+  static const Color accent = Color(0xFFFFB454); // 琥珀
+  static const Color danger = Color(0xFFE5534B);
+  static const Color text = Color(0xFFE2E8F0);
+  static const Color textDim = Color(0xFF93A1B3);
+  static const Color textFaint = Color(0xFF5B6878);
+  static const Color commandTag = Color(0xFF7C5CFF); // 命令标签紫
+
+  static ThemeData app() {
+    final base = ThemeData.dark(useMaterial3: true);
+    return base.copyWith(
+      scaffoldBackgroundColor: background,
+      colorScheme: ColorScheme.dark(
+        primary: primary,
+        secondary: accent,
+        surface: surface,
+        error: danger,
+        onPrimary: const Color(0xFF07130C),
+        onSurface: text,
+      ),
+      textTheme: base.textTheme.copyWith(
+        bodyMedium: base.textTheme.bodyMedium?.copyWith(
+          color: text,
+          fontSize: 15,
+          height: 1.5,
+        ),
+      ),
+      inputDecorationTheme: InputDecorationTheme(
+        filled: true,
+        fillColor: surfaceAlt,
+        hintStyle: const TextStyle(color: textFaint, fontSize: 15),
+        contentPadding:
+            const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
+        border: OutlineInputBorder(
+          borderRadius: BorderRadius.circular(14),
+          borderSide: BorderSide.none,
+        ),
+        focusedBorder: OutlineInputBorder(
+          borderRadius: BorderRadius.circular(14),
+          borderSide: const BorderSide(color: primaryDim, width: 1.5),
+        ),
+      ),
+    );
+  }
+}