feat: add top-seller product sections to landing page with guest browsing support

- Add two sections to landing page (Index.razor) below the hero:
  - Top 6 best-selling regular products (3-per-row grid)
  - Top 6 best-selling discount store products (3-per-row grid)
  - Each section has a 'More' button linking to /products and /discount-store
- Add GuestActionGate utility service: wraps auth-required actions; shows
  login modal for guests and resumes the original action after successful login
- Register GuestActionGate as scoped service in ConfigureServices
- Add GetTopSellingAsync(count) to ProductService and DiscountProductService
- Add optional sortBy parameter to DiscountProductService.GetProductsAsync
- Hybridize all product pages for guest browsing:
  - Store/Products, Store/ProductDetail: wrap AddToCart with GuestActionGate
  - DiscountStore/Products, DiscountStore/ProductDetail: wrap AddToCart with GuestActionGate
  - Store/Cart, DiscountStore/Cart, Store/CheckoutSummary: soft auth gate on page init
- Fix MembershipPage membership benefit text to be package-agnostic

Co-authored-by: Cursor <cursoragent@cursor.com>

src/FrontOffice.Main/Pages/Index.razor.cs

@@ -10,11 +10,22 @@ public partial class Index : IDisposable
     [Inject] private BlogPostService BlogPostService { get; set; } = default!;
     [Inject] private AuthService AuthService { get; set; } = default!;
     [Inject] private SitePageSettingsService PageSettingsService { get; set; } = default!;
+    [Inject] private ProductService ProductService { get; set; } = default!;
+    [Inject] private DiscountProductService DiscountProductService { get; set; } = default!;
+    [Inject] private CartService Cart { get; set; } = default!;
+    [Inject] private DiscountCartService DiscountCart { get; set; } = default!;
+    [Inject] private GuestActionGate GuestGate { get; set; } = default!;
+    [Inject] private VATService VAT { get; set; } = default!;
 
     // ── CMS page data ──
     private PageSettingsDto? _pageData;
     private LandingSettings? _settings;
 
+    // ── Top-selling product sections ──
+    private List<Product> _topRegularProducts = new();
+    private List<DiscountProductCard> _topDiscountProducts = new();
+    private bool _loadingTopProducts = true;
+
     // ── Latest blog posts (loaded from CMS) ──
     private List<BlogPostCardDto> _latestPosts = new();
 
@@ -51,10 +62,29 @@ public partial class Index : IDisposable
         PopulateFromSettings();
         _dataLoaded = true;
 
+        // Load top-selling products and blog posts in parallel
+        var topRegTask = ProductService.GetTopSellingAsync(6);
+        var topDiscTask = DiscountProductService.GetTopSellingAsync(6);
+        var featuredPostsTask = BlogPostService.GetFeaturedPostsAsync(2);
+
+        try
+        {
+            await Task.WhenAll(topRegTask, topDiscTask, featuredPostsTask);
+            _topRegularProducts = topRegTask.Result.Products;
+            _topDiscountProducts = topDiscTask.Result.Products;
+        }
+        catch
+        {
+            // Fallback: sections remain empty
+        }
+        _loadingTopProducts = false;
+
         // Load latest published blog posts
         try
         {
-            _latestPosts = await BlogPostService.GetFeaturedPostsAsync(2);
+            _latestPosts = featuredPostsTask.IsCompletedSuccessfully
+                ? featuredPostsTask.Result
+                : await BlogPostService.GetFeaturedPostsAsync(2);
 
             if (_latestPosts.Count < 2)
             {
@@ -267,6 +297,21 @@ public partial class Index : IDisposable
         Navigation.NavigateTo($"/blog/{slug}");
     }
 
+    private void NavigateToRegularProduct(long id)
+        => Navigation.NavigateTo(RouteConstants.Store.ProductDetail + id);
+
+    private void NavigateToDiscountProduct(long id)
+        => Navigation.NavigateTo(RouteConstants.DiscountStore.ProductDetail + id);
+
+    private async Task AddRegularToCart(Product p)
+        => await GuestGate.RunAsync(() => Cart.Add(p, 1));
+
+    private async Task AddDiscountToCart(DiscountProductCard p)
+        => await GuestGate.RunAsync(() => DiscountCart.AddAsync(p.Id));
+
+    private string FormatPrice(long price) => $"{VAT.AddVAT(price):N0} تومان";
+    private string FormatDiscountPrice(long price) => $"{price:N0} تومان";
+
     private async void OnStateChanged()
     {
         await InvokeAsync(StateHasChanged);