chore: 更新应用图标资源，添加 WebP 格式并同步各平台

- 替换所有尺寸的 app_icon.png 为新版设计
- 新增 composeResources app_icon.webp
- 同步 Android mipmap 和 iOS AppIcon 资源
- 更新 getAppIconUri 缓存版本号 (?v=2)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

shared/src/androidMain/kotlin/plus/rua/project/Platform.android.kt

@@ -16,7 +16,7 @@ actual fun getPlatform(): Platform = AndroidPlatform()
 
 actual fun getGifUri(gifFile: String): String = "file:///android_asset/gifs/$gifFile"
 
-actual fun getAppIconUri(): String = "file:///android_asset/app_icon.png"
+actual fun getAppIconUri(): String = "file:///android_asset/app_icon.png?v=2"
 
 @Composable
 actual fun PredictiveBackHandler(

shared/src/iosMain/kotlin/plus/rua/project/Platform.ios.kt

@@ -12,7 +12,7 @@ actual fun getPlatform(): Platform = IOSPlatform()
 
 actual fun getGifUri(gifFile: String): String = "compose.resource://files/$gifFile"
 
-actual fun getAppIconUri(): String = "compose.resource://files/app_icon.png"
+actual fun getAppIconUri(): String = "compose.resource://files/app_icon.png?v=2"
 
 @Composable
 actual fun PredictiveBackHandler(