feat: Implement Zalo and MktX services with API controllers, add web client pages for Auth and Products, and update client navigation and styling.

apps/web-client-base-net/src/WebClientBase.Client/Layout/MainLayout.razor

@@ -1,16 +1,60 @@
 @inherits LayoutComponentBase
-<div class="page">
-    <div class="sidebar">
+@inject IJSRuntime JS
+
+@* 
+    EN: Main layout with sidebar navigation and theme toggle.
+    VI: Layout chính với sidebar navigation và theme toggle.
+*@
+
+<div class="page" data-theme="@currentTheme">
+    <aside class="sidebar">
         <NavMenu />
-    </div>
+    </aside>
 
     <main>
-        <div class="top-row px-4">
-            <a href="https://learn.microsoft.com/aspnet/core/" target="_blank">About</a>
-        </div>
+        <header class="top-row">
+            <button class="theme-toggle" @onclick="ToggleTheme" title="Toggle theme / Đổi theme">
+                @if (currentTheme == "dark")
+                {
+                    <span>☀️ Light</span>
+                }
+                else
+                {
+                    <span>🌙 Dark</span>
+                }
+            </button>
+        </header>
 
-        <article class="content px-4">
+        <article class="content">
             @Body
         </article>
     </main>
 </div>
+
+@code {
+    private string currentTheme = "light";
+
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (firstRender)
+        {
+            // EN: Load saved theme from localStorage
+            // VI: Tải theme đã lưu từ localStorage
+            var savedTheme = await JS.InvokeAsync<string>("localStorage.getItem", "theme");
+            if (!string.IsNullOrEmpty(savedTheme))
+            {
+                currentTheme = savedTheme;
+                StateHasChanged();
+            }
+        }
+    }
+
+    private async Task ToggleTheme()
+    {
+        currentTheme = currentTheme == "dark" ? "light" : "dark";
+        
+        // EN: Save theme to localStorage
+        // VI: Lưu theme vào localStorage
+        await JS.InvokeVoidAsync("localStorage.setItem", "theme", currentTheme);
+    }
+}