Fix flickering status card on app startup

app/src/main/java/sh/sar/isodroid/viewmodel/MainViewModel.kt

@@ -178,6 +178,8 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
                 loadFiles()
                 checkMountStatus()
             }
+        } else {
+            _uiState.update { it.copy(isSupported = false) }
         }
 
         _uiState.update { it.copy(isLoading = false) }
@@ -380,7 +382,7 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
         viewModelScope.launch {
             // Check cached status (no popup)
             val cachedStatus = RootManager.isRootGrantedCached()
-            if (cachedStatus == true && !_uiState.value.hasRoot) {
+            if (cachedStatus == true && _uiState.value.hasRoot != true) {
                 // Root was granted externally (e.g., in Magisk settings)
                 _uiState.update { it.copy(hasRoot = true, rootDenied = false) }
 
@@ -546,9 +548,9 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
 
 data class MainUiState(
     val isLoading: Boolean = true,
-    val hasRoot: Boolean = false,
+    val hasRoot: Boolean? = null, // null = checking, true = granted, false = denied
     val rootDenied: Boolean = false, // True if user denied root in Magisk
-    val isSupported: Boolean = false,
+    val isSupported: Boolean? = null, // null = checking, true = supported, false = not supported
     val mountStatus: MountStatus = MountStatus.UNMOUNTED,
     val isoFiles: List<IsoFile> = emptyList(),
     val currentPath: String = "",