Add tablet navigation drawer to shell

src/RolemasterDb.App/Components/Shell/AppShell.razor

@@ -1,3 +1,6 @@
+@implements IDisposable
+@inject NavigationManager NavigationManager
+
 <div class="app-shell">
     <a class="skip-link" href="#app-main">Skip to main content</a>
 
@@ -39,6 +42,17 @@
             </div>
 
             <div class="app-shell-header-actions">
+                <button
+                    type="button"
+                    class="app-shell-menu-toggle"
+                    aria-expanded="@isNavMenuOpen"
+                    aria-controls="app-shell-drawer"
+                    @onclick="ToggleNavMenu">
+                    <span class="app-shell-menu-toggle-bar"></span>
+                    <span class="app-shell-menu-toggle-bar"></span>
+                    <span class="app-shell-menu-toggle-bar"></span>
+                    <span class="visually-hidden">Toggle navigation</span>
+                </button>
                 @UtilityContent
             </div>
         </div>
@@ -57,6 +71,26 @@
         </div>
     </main>
 
+    @if (isNavMenuOpen)
+    {
+        <button
+            type="button"
+            class="app-shell-drawer-backdrop"
+            aria-label="Close navigation"
+            @onclick="CloseNavMenu"></button>
+
+        <aside id="app-shell-drawer" class="app-shell-drawer" aria-label="Primary navigation">
+            <div class="app-shell-drawer-header">
+                <strong>Navigate</strong>
+                <button type="button" class="app-shell-drawer-close" @onclick="CloseNavMenu">
+                    Close
+                </button>
+            </div>
+
+            <ShellPrimaryNav />
+        </aside>
+    }
+
     <nav class="app-shell-mobile-nav" aria-label="Primary">
         <ShellPrimaryNav IsBottomNav="true" />
     </nav>
@@ -80,4 +114,32 @@
 
     [Parameter]
     public RenderFragment? UtilityContent { get; set; }
+
+    private bool isNavMenuOpen;
+
+    protected override void OnInitialized()
+    {
+        NavigationManager.LocationChanged += HandleLocationChanged;
+    }
+
+    private void ToggleNavMenu()
+    {
+        isNavMenuOpen = !isNavMenuOpen;
+    }
+
+    private void CloseNavMenu()
+    {
+        isNavMenuOpen = false;
+    }
+
+    private void HandleLocationChanged(object? sender, LocationChangedEventArgs args)
+    {
+        isNavMenuOpen = false;
+        _ = InvokeAsync(StateHasChanged);
+    }
+
+    public void Dispose()
+    {
+        NavigationManager.LocationChanged -= HandleLocationChanged;
+    }
 }