Fix HTTP 500 login error: Configure anti-forgery and routing for proxy

- Re-enabled ValidateAntiForgeryToken attribute
- Configured anti-forgery for proxy environments with SameAsRequest
- Fixed area routing order and constraints
- Added proper forwarded headers middleware

LittleShop/Areas/Admin/Controllers/AccountController.cs

@@ -28,7 +28,7 @@ public class AccountController : Controller
     }
 
     [HttpPost]
-    // [ValidateAntiForgeryToken] // Temporarily disabled for HTTPS proxy issue
+    [ValidateAntiForgeryToken]
     public async Task<IActionResult> Login(string username, string password)
     {
         Console.WriteLine($"Received Username: '{username}', Password: '{password}'");