feat(web): add auth and fix deployment checks

src/dotnet/QuantEngine.Web/Client/Pages/Login.razor

@@ -14,7 +14,7 @@
             <p class="brand-subtitle">은퇴자산포트폴리오 투자 관리 시스템</p>
         </div>
 
-        <form @onsubmit="HandleLoginAsync" class="auth-form">
+        <form @onsubmit="HandleLoginAsync" @onsubmit:preventDefault="true" class="auth-form">
             <div class="form-group">
                 <label for="username">관리자 아이디</label>
                 <input type="text" id="username" class="form-control" @bind="Username" placeholder="아이디를 입력하세요" autocomplete="username" />
@@ -268,6 +268,15 @@
     private string ErrorMessage { get; set; } = string.Empty;
     private bool IsSubmitting { get; set; } = false;
 
+    private sealed class LoginResponse
+    {
+        public bool Success { get; set; }
+        public string? Username { get; set; }
+        public string? Role { get; set; }
+        public string? AccessToken { get; set; }
+        public string? ExpiresAt { get; set; }
+    }
+
     private async Task HandleLoginAsync()
     {
         ErrorMessage = string.Empty;
@@ -285,8 +294,15 @@
 
             if (response.IsSuccessStatusCode)
             {
+                var auth = await response.Content.ReadFromJsonAsync<LoginResponse>();
+                if (auth is null || string.IsNullOrWhiteSpace(auth.AccessToken))
+                {
+                    ErrorMessage = "로그인 응답이 유효하지 않습니다.";
+                    return;
+                }
+
                 var customProvider = (CustomAuthenticationStateProvider)AuthStateProvider;
-                await customProvider.MarkUserAsAuthenticatedAsync(Username);
+                await customProvider.MarkUserAsAuthenticatedAsync(auth.Username ?? Username, auth.AccessToken, auth.Role ?? "Admin");
                 
                 // Redirect back to home dashboard
                 NavigationManager.NavigateTo("");