fix: Web and input device switching in video player

lib/widgets/shared/back_intent_dpad.dart

@@ -0,0 +1,42 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+import 'package:auto_route/auto_route.dart';
+
+import 'package:fladder/util/adaptive_layout/adaptive_layout.dart';
+
+class BackIntentDpad extends StatelessWidget {
+  final Widget child;
+  const BackIntentDpad({required this.child, super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    if (AdaptiveLayout.inputDeviceOf(context) == InputDevice.touch) {
+      return child;
+    }
+    return Shortcuts(
+      shortcuts: <LogicalKeySet, Intent>{
+        LogicalKeySet(LogicalKeyboardKey.backspace): const BackIntent(),
+      },
+      child: Actions(
+        actions: <Type, Action<Intent>>{
+          BackIntent: CallbackAction<BackIntent>(
+            onInvoke: (intent) async {
+              final navigator = await context.maybePop();
+              if (navigator) {
+                return true;
+              } else {
+                return false;
+              }
+            },
+          ),
+        },
+        child: child,
+      ),
+    );
+  }
+}
+
+class BackIntent extends Intent {
+  const BackIntent();
+}