chore: 清理项目中多余的示例、依赖和资源文件

本次提交删除了大量冗余的平台配置文件、示例项目构建产物、测试资源文件以及第三方插件的无关代码，包括：
1. 移除了fluttertoast、liquid_glass_easy等插件的全量示例项目文件
2. 删除了本地依赖的ohos模块缓存和构建配置
3. 清理了各种平台的图标、资源文件和gitignore配置
4. 调整了主项目安卓最小SDK版本配置
5. 添加了macos运行需要的权限配置

android/app/build.gradle.kts

@@ -25,7 +25,7 @@ android {
         applicationId = "apps.xy.xianyan"
         // You can update the following values to match your application needs.
         // For more information, see: https://flutter.dev/to/review-gradle-config.
-        minSdk = 26
+        minSdk = 28
         targetSdk = flutter.targetSdkVersion
         versionCode = flutter.versionCode
         versionName = flutter.versionName

android/app/src/main/AndroidManifest.xml

@@ -61,12 +61,7 @@
         android:name="android.hardware.usb.host"
         android:required="false" />
 
-    <!-- ============================================================ -->
-    <!-- 前台服务 — 屏幕共享 (F3)                                      -->
-    <!-- Android 14+ 需要 FOREGROUND_SERVICE_MEDIA_PROJECTION         -->
-    <!-- ============================================================ -->
-    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
-    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PROJECTION" />
+
 
     <application
         android:label="闲言"