feat: save window size and resize on startup (#332)

ui/flutter/lib/util/util.dart

@@ -143,4 +143,12 @@ class Util {
     }
     return completer.future;
   }
+
+  static void Function() debounce(Function() fn, int ms) {
+    Timer? timer;
+    return () {
+      timer?.cancel();
+      timer = Timer(Duration(milliseconds: ms), fn);
+    };
+  }
 }

ui/flutter/lib/util/window_util.dart

@@ -0,0 +1,39 @@
+import 'dart:async';
+
+import 'package:shared_preferences/shared_preferences.dart';
+
+class WindowState {
+  late bool isMaximized;
+  late double width;
+  late double height;
+
+  WindowState(this.isMaximized, this.width, this.height);
+}
+
+const String _windowStateIsMaximized = "window.isMaximized";
+const String _windowStateWidth = "window.width";
+const String _windowStateHeight = "window.height";
+
+/// Save window state to storage.
+void saveState({bool? isMaximized, double? width, double? height}) async {
+  final prefs = await SharedPreferences.getInstance();
+  if (isMaximized != null) {
+    await prefs.setBool(_windowStateIsMaximized, isMaximized);
+  }
+  if (width != null) {
+    await prefs.setDouble(_windowStateWidth, width);
+  }
+  if (height != null) {
+    await prefs.setDouble(_windowStateHeight, height);
+  }
+}
+
+/// Load window state from storage.
+Future<WindowState> loadState() async {
+  final prefs = await SharedPreferences.getInstance();
+  return WindowState(
+    prefs.getBool(_windowStateIsMaximized) ?? false,
+    prefs.getDouble(_windowStateWidth) ?? 800,
+    prefs.getDouble(_windowStateHeight) ?? 600,
+  );
+}