feat: H5热更新 v6→v7 — 远端version.txt=v7 + index-v7.html

- ota/version.txt → 0.1.0-dav-android-7
- ota/h5/index-v7.html → 绿色标题+✅热更新成功提示
- embedded index.html → 下载目标改为v7

packages/client-android/android/build.gradle

@@ -12,7 +12,7 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        classpath("com.android.tools.build:gradle:8.7.3")
+        classpath('com.android.tools.build:gradle:8.13.2')
         classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlinVersion}")
     }
 }