fix(admin-layout): fix Guest display, error bar, empty shops

- Subscribe to AuthState.OnChange to refresh user info after login
- Call TryRestoreSessionAsync on first render to restore from localStorage
- Wrap Body in ErrorBoundary with custom UI (replaces red error bar)
- Properly unsubscribe OnChange in Dispose to prevent memory leaks

apps/web-client-tpos-net/src/WebClientTpos.Client/Layout/AdminLayout.razor

@@ -134,14 +134,32 @@
 
     @* ═══ MAIN AREA ═══ *@
     <main class="admin-main">
-        <CascadingValue Value="this">
-            @Body
-        </CascadingValue>
+        <ErrorBoundary @ref="_errorBoundary">
+            <ChildContent>
+                <CascadingValue Value="this">
+                    @Body
+                </CascadingValue>
+            </ChildContent>
+            <ErrorContent>
+                <div style="text-align:center;padding:48px 20px;">
+                    <div style="width:64px;height:64px;border-radius:20px;background:rgba(239,68,68,0.1);display:flex;align-items:center;justify-content:center;margin:0 auto 16px;">
+                        <i data-lucide="alert-triangle" style="width:28px;height:28px;color:#EF4444;"></i>
+                    </div>
+                    <h3 style="font-size:16px;font-weight:700;margin:0 0 8px;color:#EF4444;">Đã xảy ra lỗi</h3>
+                    <p style="font-size:13px;color:var(--admin-text-tertiary);margin:0 0 16px;">Trang gặp sự cố. Vui lòng tải lại.</p>
+                    <button class="admin-btn-primary" @onclick="RecoverError" style="display:inline-flex;align-items:center;gap:8px;">
+                        <i data-lucide="refresh-cw" style="width:14px;height:14px;"></i>
+                        Tải lại
+                    </button>
+                </div>
+            </ErrorContent>
+        </ErrorBoundary>
     </main>
 </div>
 
 @code {
     private bool _sidebarOpen = false;
+    private ErrorBoundary? _errorBoundary;
 
     // EN: Shop context detection — parsed from URL
     // VI: Phát hiện context cửa hàng — parse từ URL
@@ -153,16 +171,29 @@
     protected override void OnInitialized()
     {
         NavigationManager.LocationChanged += OnLocationChanged;
+        // EN: Subscribe to auth state changes so user display refreshes after login/logout
+        // VI: Subscribe auth state để cập nhật user display sau login/logout
+        AuthState.OnChange += OnAuthStateChanged;
         DetectShopContext();
     }
 
     protected override async Task OnAfterRenderAsync(bool firstRender)
     {
+        if (firstRender)
+        {
+            // EN: Restore session from localStorage on first render (Blazor WASM ready)
+            // VI: Khôi phục session từ localStorage khi render lần đầu (Blazor WASM sẵn sàng)
+            await AuthSvc.TryRestoreSessionAsync();
+        }
         // EN: Re-init Lucide icons after every render (Blazor navigation replaces DOM)
         // VI: Khởi tạo lại Lucide icons sau mỗi lần render (Blazor navigation thay đổi DOM)
         try { await JS.InvokeVoidAsync("lucide.createIcons"); } catch { }
     }
 
+    private void OnAuthStateChanged() => InvokeAsync(StateHasChanged);
+
+    private void RecoverError() => _errorBoundary?.Recover();
+
     private void OnLocationChanged(object? sender, Microsoft.AspNetCore.Components.Routing.LocationChangedEventArgs e)
     {
         DetectShopContext();
@@ -251,5 +282,6 @@
     public void Dispose()
     {
         NavigationManager.LocationChanged -= OnLocationChanged;
+        AuthState.OnChange -= OnAuthStateChanged;
     }
 }