feat(admin): restore Blazor WebAssembly architecture for admin pages with hybrid Server routing

TaxBaik.Web.Client/Services/TokenRefreshHandler.cs

@@ -0,0 +1,106 @@
+namespace TaxBaik.Web.Services;
+
+using System.Net;
+using System.Text.Json;
+
+/// <summary>
+/// HTTP 요청 시 자동으로 access token을 추가하고,
+/// 401 응답을 받으면 refresh token으로 새 토큰을 획득한 후 재시도합니다.
+/// SOLID: Single Responsibility - 토큰 갱신 로직만 담당
+/// </summary>
+public class TokenRefreshHandler : DelegatingHandler
+{
+    private readonly IServiceProvider _serviceProvider;
+    private readonly ILogger<TokenRefreshHandler> _logger;
+
+    public TokenRefreshHandler(IServiceProvider serviceProvider, ILogger<TokenRefreshHandler> logger)
+    {
+        _serviceProvider = serviceProvider;
+        _logger = logger;
+    }
+
+    protected override async Task<HttpResponseMessage> SendAsync(
+        HttpRequestMessage request,
+        CancellationToken cancellationToken)
+    {
+        // 최신 Scoped ITokenStore 실시간 해석 (Scope Capture 차단 및 기존 Blazor 회로 수명 공유)
+        var tokenStore = Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService<ITokenStore>(_serviceProvider);
+
+        // 요청에 access token 추가
+        if (!string.IsNullOrEmpty(tokenStore.AccessToken))
+        {
+            request.Headers.Authorization = new("Bearer", tokenStore.AccessToken);
+        }
+
+        var response = await base.SendAsync(request, cancellationToken);
+
+        // 401 응답이면 토큰 갱신 시도
+        if (response.StatusCode == HttpStatusCode.Unauthorized)
+        {
+            if (!string.IsNullOrEmpty(tokenStore.RefreshToken))
+            {
+                var newTokenPair = await RefreshTokenAsync(tokenStore.RefreshToken, request, cancellationToken);
+                if (newTokenPair != null)
+                {
+                    // TokenStore에 토큰 저장
+                    tokenStore.AccessToken = newTokenPair.AccessToken;
+                    tokenStore.RefreshToken = newTokenPair.RefreshToken;
+                    tokenStore.TokenExpiryTicks = DateTime.UtcNow.AddSeconds(newTokenPair.ExpiresIn).Ticks;
+
+                    // 새 토큰으로 재요청
+                    request.Headers.Authorization = new("Bearer", newTokenPair.AccessToken);
+                    response = await base.SendAsync(request, cancellationToken);
+                }
+                else
+                {
+                    _logger.LogWarning("토큰 갱신 실패 - 로그아웃");
+                    tokenStore.Clear();
+                }
+            }
+        }
+
+        return response;
+    }
+
+    private async Task<WasmAuthTokenPair?> RefreshTokenAsync(string refreshToken, HttpRequestMessage originalRequest, CancellationToken ct)
+    {
+        try
+        {
+            // 원래 요청의 호스트 정보 추출
+            var authority = originalRequest.RequestUri?.Authority ?? "localhost:5001";
+            var scheme = originalRequest.RequestUri?.Scheme ?? "http";
+
+            using var httpClient = new HttpClient();
+            var refreshUri = new Uri($"{scheme}://{authority}/taxbaik/api/auth/refresh");
+            var json = JsonSerializer.Serialize(new { refreshToken });
+            var content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");
+
+            var response = await httpClient.PostAsync(refreshUri, content, ct);
+            if (!response.IsSuccessStatusCode)
+            {
+                _logger.LogWarning($"Token refresh failed with status {response.StatusCode}");
+                return null;
+            }
+
+            var responseContent = await response.Content.ReadAsStringAsync(ct);
+            var result = JsonSerializer.Deserialize<AuthTokenResponse>(responseContent,
+                new JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+
+            return result != null
+                ? new WasmAuthTokenPair(result.AccessToken, result.RefreshToken, result.ExpiresIn)
+                : null;
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Exception during token refresh");
+            return null;
+        }
+    }
+}
+
+internal class AuthTokenResponse
+{
+    public string AccessToken { get; set; } = string.Empty;
+    public string RefreshToken { get; set; } = string.Empty;
+    public int ExpiresIn { get; set; }
+}