fix: enforce min window size and pin navigation sidebar (#293)

Resolved conflict with current master, preserving navigation pane persistence while keeping the wider minimum size and dynamic pane width.\n\nValidation: local ARM64 build passed; Shared tests 1296 passed / 20 skipped; Tray tests 466 passed; remote CI green.\n\nCo-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/OpenClaw.Tray.WinUI/Windows/HubWindow.xaml

@@ -5,7 +5,7 @@
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:winex="using:WinUIEx"
     Title="OpenClaw"
-    MinWidth="600" MinHeight="400">
+    MinWidth="750" MinHeight="400">
 
     <Window.SystemBackdrop>
         <MicaBackdrop/>

src/OpenClaw.Tray.WinUI/Windows/HubWindow.xaml.cs

@@ -83,10 +83,22 @@ public sealed partial class HubWindow : WindowEx
         this.CenterOnScreen();
         this.SetIcon(IconHelper.GetStatusIconPath(ConnectionStatus.Connected));
 
+        RootGrid.SizeChanged += OnRootGridSizeChanged;
+
         // Don't select a nav item here — Settings/GatewayClient aren't set yet.
         // ShowHub() in App.xaml.cs calls NavigateToDefault() after setting properties.
     }
 
+    private void OnRootGridSizeChanged(object sender, SizeChangedEventArgs e)
+    {
+        const double minPane = 200;
+        const double maxPane = 320;
+        const double ratio = 0.25;
+
+        double desired = e.NewSize.Width * ratio;
+        NavView.OpenPaneLength = Math.Clamp(desired, minPane, maxPane);
+    }
+
     /// <summary>
     /// Navigate to the default page. Call after setting Settings/GatewayClient.
     /// </summary>