Request storage permission on app launch

Automatically prompts for "All files access" (Android 11+) or
READ/WRITE_EXTERNAL_STORAGE (older) when the app starts, so /sdcard
is accessible in proot without needing to manually go to Settings.

Co-Authored-By: Mithun Gowda B <mithungowda.b7411@gmail.com>

Author: mithun50

flutter_app/android/app/src/main/kotlin/com/nxg/openclawproot/MainActivity.kt

@@ -475,6 +475,7 @@ class MainActivity : FlutterActivity() {
 
         createUrlNotificationChannel()
         requestNotificationPermission()
+        requestStoragePermissionOnLaunch()
 
         EventChannel(flutterEngine.dartExecutor.binaryMessenger, EVENT_CHANNEL).setStreamHandler(
             object : EventChannel.StreamHandler {
@@ -502,6 +503,30 @@ class MainActivity : FlutterActivity() {
         }
     }
 
+    private fun requestStoragePermissionOnLaunch() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+            if (!Environment.isExternalStorageManager()) {
+                try {
+                    val intent = Intent(Settings.ACTION_MANAGE_ALL_FILES_ACCESS_PERMISSION)
+                    startActivity(intent)
+                } catch (_: Exception) {}
+            }
+        } else {
+            if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
+                != PackageManager.PERMISSION_GRANTED
+            ) {
+                ActivityCompat.requestPermissions(
+                    this,
+                    arrayOf(
+                        Manifest.permission.READ_EXTERNAL_STORAGE,
+                        Manifest.permission.WRITE_EXTERNAL_STORAGE
+                    ),
+                    STORAGE_PERMISSION_REQUEST
+                )
+            }
+        }
+    }
+
     private fun createUrlNotificationChannel() {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             val channel = NotificationChannel(