Keep the screen on in flight, time out silent vision starts, gate Tripod on the ground

From the Mavic Pro simulator run on 2026-10-22:
- The tablet's 2-minute sleep blanked the flight screen mid-flight. The
  flight screen now sets FLAG_KEEP_SCREEN_ON while it is open.
- TapFly's GO got no answer from the aircraft and no error, so the button
  looked dead. ActiveTrack/TapFly starts now give up after 15 s with "the
  aircraft did not answer".
- Tripod works in the air but the flight controller ignores it on the
  ground, so the gate asks to take off first.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Fly App/android/app/src/main/kotlin/com/pilotvault/flyapp/MainActivity.kt

@@ -4,10 +4,12 @@ import android.Manifest
 import android.content.pm.PackageManager
 import android.os.Build
 import android.os.Bundle
+import android.view.WindowManager
 import androidx.core.app.ActivityCompat
 import androidx.core.content.ContextCompat
 import io.flutter.embedding.android.FlutterFragmentActivity
 import io.flutter.embedding.engine.FlutterEngine
+import io.flutter.plugin.common.MethodChannel
 
 // FlutterFragmentActivity (not FlutterActivity) is required by local_auth so the
 // platform BiometricPrompt can attach to a FragmentActivity host.
@@ -21,6 +23,16 @@ class MainActivity : FlutterFragmentActivity() {
         // Live DJI video feed rendered behind the Flight Control HUD.
         flutterEngine.platformViewsController.registry
             .registerViewFactory(DjiVideoView.VIEW_TYPE, DjiVideoViewFactory())
+        // The flight screen keeps the display on (see ScreenAwake in Dart).
+        MethodChannel(flutterEngine.dartExecutor.binaryMessenger, "pilotvault/screen").setMethodCallHandler { call, result ->
+            if (call.method == "keepOn") {
+                if (call.arguments == true) window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+                else window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+                result.success(null)
+            } else {
+                result.notImplemented()
+            }
+        }
     }
 
     override fun onCreate(savedInstanceState: Bundle?) {