Hide settings rows whose key the aircraft cannot read

The Mavic Pro remote reports GIMBAL_CONTROL_SPEED_COEFFICIENT as supported but
fails every read, so "Gimbal dial speed" sat on "—" forever. The key bridge
now reports a failed seeding read, and the row hides like an unsupported one
until a value does arrive.

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

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

@@ -113,7 +113,11 @@ class KeyBridge(private val ctx: BridgeCtx) : SubBridge {
                         ctx.emit(mapOf("type" to "key", "id" to id, "value" to KeyValues.toDart(value)))
                     }
 
-                    override fun onFailure(error: DJIError) = Unit
+                    // Supported but unreadable (the Mavic Pro remote's gimbal dial
+                    // speed): say so, or the row waits on "—" forever.
+                    override fun onFailure(error: DJIError) {
+                        ctx.emit(mapOf("type" to "key", "id" to id, "unreadable" to true))
+                    }
                 })
                 result.success(id)
             }

Fly App/lib/fly/state/key_state.dart

@@ -25,8 +25,17 @@ class KeyState extends ChangeNotifier with SettingsOverlay {
     notifyListeners();
   }
 
+  /// A key the aircraft calls supported but will not read: hidden like an
+  /// unsupported one, until a value turns up after all.
+  void markUnreadable(String id) {
+    if (_supported[id] == false || reportedSettings.containsKey(id)) return;
+    _supported[id] = false;
+    notifyListeners();
+  }
+
   /// One `key` event: `{id, value}`.
   void apply(String id, Object? value) {
+    if (_supported[id] == false) _supported.remove(id);
     replaceReported(<String, dynamic>{...reportedSettings, id: value});
     notifyListeners();
   }

Fly App/lib/fly/telemetry_reducer.dart

@@ -49,7 +49,12 @@ class TelemetryReducer {
         return true;
       case 'key':
         final String? id = asString(event['id']);
-        if (model.connected && id != null) model.keys.apply(id, event['value']);
+        if (!model.connected || id == null) return true;
+        if (event['unreadable'] == true) {
+          model.keys.markUnreadable(id);
+        } else {
+          model.keys.apply(id, event['value']);
+        }
         return true;
       case 'mission':
         model.mission.apply(event);

Fly App/test/fly/settings_test.dart

@@ -146,6 +146,17 @@ void main() {
       expect(m.keys.value(SettingsKeys.novice), isNull);
     });
 
+    test('a supported key that cannot be read hides its row until a value arrives', () {
+      final FlightModel m = connectedModel(phantom4);
+      final TelemetryReducer r = TelemetryReducer(m);
+      m.keys.setSupported(SettingsKeys.gimbalDialSpeed, true);
+      r.apply(<String, dynamic>{'type': 'key', 'id': SettingsKeys.gimbalDialSpeed.id, 'unreadable': true});
+      expect(m.keys.supported(SettingsKeys.gimbalDialSpeed), isFalse);
+      r.apply(<String, dynamic>{'type': 'key', 'id': SettingsKeys.gimbalDialSpeed.id, 'value': 40});
+      expect(m.keys.supported(SettingsKeys.gimbalDialSpeed), isNot(isFalse));
+      expect(m.keys.value(SettingsKeys.gimbalDialSpeed), 40);
+    });
+
     test('subscriptions listen only to supported keys and cancel on dispose', () async {
       final FakeDjiService dji = FakeDjiService()..unsupportedKeys.add('ESC_BEEPING_ENABLED');
       final KeyState s = KeyState();