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

TaxBaik.Web.Client/GlobalUsings.cs

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+global using System.Net.Http;
+global using System.Net.Http.Json;

TaxBaik.Web.Client/Pages/WasmPing.razor

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+@* WASM 기반(M3) 검증용 컴포넌트. 라우팅/렌더모드 전면 적용은 M4에서 처리한다. *@
+@rendermode InteractiveWebAssembly
+
+<MudPaper Class="pa-6 ma-4" Elevation="2">
+    <MudText Typo="Typo.h5" GutterBottom="true">WebAssembly 렌더 모드 점검</MudText>
+    <MudText Typo="Typo.body2" Class="mb-4">이 컴포넌트가 클릭에 반응하면 Interactive WebAssembly 기반이 정상 동작하는 것입니다.</MudText>
+    <MudButton Variant="Variant.Filled" Color="Color.Primary" OnClick="Increment">카운트: @count</MudButton>
+</MudPaper>
+
+@code {
+    private int count;
+    private void Increment() => count++;
+}

TaxBaik.Web.Client/Program.cs

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+using Microsoft.AspNetCore.Components.Authorization;
+using Microsoft.AspNetCore.Components.WebAssembly.Hosting;
+using MudBlazor.Services;
+using TaxBaik.Application.Services;
+using TaxBaik.Web.Services;
+using TaxBaik.Web.Services.AdminClients;
+
+var builder = WebAssemblyHostBuilder.CreateDefault(args);
+
+// MudBlazor (WASM 측 인터랙티브 컴포넌트용)
+builder.Services.AddMudServices(config =>
+{
+    config.SnackbarConfiguration.HideTransitionDuration = 400;
+    config.SnackbarConfiguration.ShowTransitionDuration = 300;
+    config.PopoverOptions.ThrowOnDuplicateProvider = false;
+});
+
+// API Base Url 동적 구성 (호스트 기준 /taxbaik/api/)
+var apiBaseUrl = builder.HostEnvironment.BaseAddress.TrimEnd('/') + "/taxbaik/api/";
+
+// HTTP Client for API (with automatic token refresh)
+builder.Services.AddScoped<ITokenStore, TokenStore>();
+builder.Services.AddScoped<TokenRefreshHandler>();
+
+builder.Services.AddHttpClient<IApiClient, ApiClient>(client =>
+{
+    client.BaseAddress = new Uri(apiBaseUrl);
+}).AddHttpMessageHandler<TokenRefreshHandler>();
+
+// 각 Browser API Client 등록
+builder.Services.AddHttpClient<IAdminDashboardClient, AdminDashboardClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+builder.Services.AddHttpClient<IInquiryBrowserClient, InquiryBrowserClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+builder.Services.AddHttpClient<IClientBrowserClient, ClientBrowserClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+builder.Services.AddHttpClient<ITaxFilingBrowserClient, TaxFilingBrowserClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+builder.Services.AddHttpClient<IFaqBrowserClient, FaqBrowserClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+builder.Services.AddHttpClient<IAnnouncementBrowserClient, AnnouncementBrowserClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+builder.Services.AddHttpClient<ITaxProfileBrowserClient, TaxProfileBrowserClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+builder.Services.AddHttpClient<ITaxFilingScheduleBrowserClient, TaxFilingScheduleBrowserClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+builder.Services.AddHttpClient<IConsultingActivityBrowserClient, ConsultingActivityBrowserClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+builder.Services.AddHttpClient<IContractBrowserClient, ContractBrowserClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+builder.Services.AddHttpClient<IRevenueTrackingBrowserClient, RevenueTrackingBrowserClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+builder.Services.AddHttpClient<ICommonCodeBrowserClient, CommonCodeBrowserClient>(client => client.BaseAddress = new Uri(apiBaseUrl)).AddHttpMessageHandler<TokenRefreshHandler>();
+
+// Blazor 인증 (WASM 측 클라이언트)
+builder.Services.AddScoped<CustomAuthenticationStateProvider>();
+builder.Services.AddScoped<AuthenticationStateProvider>(sp => sp.GetRequiredService<CustomAuthenticationStateProvider>());
+builder.Services.AddScoped<ILocalStorageService, LocalStorageService>();
+builder.Services.AddCascadingAuthenticationState();
+builder.Services.AddAuthorizationCore();
+
+await builder.Build().RunAsync();

TaxBaik.Web.Client/Services/AdminClients/ICommonCodeBrowserClient.cs

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+namespace TaxBaik.Web.Services.AdminClients;
+
+using System.Collections.Generic;
+using System.Net.Http.Json;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using TaxBaik.Domain.Entities;
+using Microsoft.Extensions.Logging;
+
+public interface ICommonCodeBrowserClient
+{
+    Task<List<CommonCode>> GetAllActiveAsync(CancellationToken ct = default);
+    Task<List<CommonCode>> GetByGroupAsync(string group, CancellationToken ct = default);
+}
+
+public class CommonCodeBrowserClient(HttpClient httpClient, ITokenStore tokenStore, ILogger<CommonCodeBrowserClient> logger) : ICommonCodeBrowserClient
+{
+    private const string BaseUrl = "/api/commoncode";
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(tokenStore.AccessToken))
+            httpClient.DefaultRequestHeaders.Authorization = new("Bearer", tokenStore.AccessToken);
+        else
+            httpClient.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<List<CommonCode>> GetAllActiveAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<CommonCode>>($"{BaseUrl}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get all active common codes");
+            return [];
+        }
+    }
+
+    public async Task<List<CommonCode>> GetByGroupAsync(string group, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<CommonCode>>($"{BaseUrl}/group/{group}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get common codes for group {Group}", group);
+            return [];
+        }
+    }
+}

TaxBaik.Web.Client/Services/AdminClients/IConsultingActivityBrowserClient.cs

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+namespace TaxBaik.Web.Services.AdminClients;
+
+using System.Text.Json;
+using TaxBaik.Domain.Entities;
+
+public interface IConsultingActivityBrowserClient
+{
+    Task<List<ConsultingActivity>> GetAllAsync(CancellationToken ct = default);
+    Task<List<ConsultingActivity>> GetByClientIdAsync(int clientId, CancellationToken ct = default);
+    Task<List<ConsultingActivity>> GetPendingFollowupsAsync(CancellationToken ct = default);
+    Task<int> CreateAsync(int clientId, string activityType, DateTime activityDate, string description,
+        int? consultantId = null, DateTime? nextFollowupDate = null, CancellationToken ct = default);
+    Task UpdateAsync(int id, string? outcome = null, DateTime? nextFollowupDate = null, CancellationToken ct = default);
+    Task DeleteAsync(int id, CancellationToken ct = default);
+}
+
+public class ConsultingActivityBrowserClient(HttpClient httpClient, ITokenStore tokenStore, ILogger<ConsultingActivityBrowserClient> logger)
+    : IConsultingActivityBrowserClient
+{
+    private const string BaseUrl = "/api/consultingactivity";
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(tokenStore.AccessToken))
+            httpClient.DefaultRequestHeaders.Authorization = new("Bearer", tokenStore.AccessToken);
+        else
+            httpClient.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<List<ConsultingActivity>> GetAllAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<ConsultingActivity>>($"{BaseUrl}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get consulting activities");
+            return [];
+        }
+    }
+
+    public async Task<List<ConsultingActivity>> GetByClientIdAsync(int clientId, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<ConsultingActivity>>($"{BaseUrl}/client/{clientId}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get activities for client {ClientId}", clientId);
+            return [];
+        }
+    }
+
+    public async Task<List<ConsultingActivity>> GetPendingFollowupsAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.GetFromJsonAsync<JsonElement>($"{BaseUrl}/pending-followups", ct);
+            if (response.TryGetProperty("data", out var data))
+                return System.Text.Json.JsonSerializer.Deserialize<List<ConsultingActivity>>(data.GetRawText()) ?? [];
+            return [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get pending followups");
+            return [];
+        }
+    }
+
+    public async Task<int> CreateAsync(int clientId, string activityType, DateTime activityDate, string description,
+        int? consultantId = null, DateTime? nextFollowupDate = null, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var request = new { clientId, activityType, activityDate, description, consultantId, nextFollowupDate };
+            var response = await httpClient.PostAsJsonAsync(BaseUrl, request, ct);
+            response.EnsureSuccessStatusCode();
+            var result = await response.Content.ReadFromJsonAsync<JsonElement>(cancellationToken: ct);
+            return result.TryGetProperty("id", out var idProp) ? idProp.GetInt32() : 0;
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to create consulting activity");
+            return 0;
+        }
+    }
+
+    public async Task UpdateAsync(int id, string? outcome = null, DateTime? nextFollowupDate = null, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var request = new { outcome, nextFollowupDate };
+            var response = await httpClient.PutAsJsonAsync($"{BaseUrl}/{id}", request, ct);
+            response.EnsureSuccessStatusCode();
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to update consulting activity {Id}", id);
+        }
+    }
+
+    public async Task DeleteAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.DeleteAsync($"{BaseUrl}/{id}", ct);
+            response.EnsureSuccessStatusCode();
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to delete consulting activity {Id}", id);
+        }
+    }
+}

TaxBaik.Web.Client/Services/AdminClients/IContractBrowserClient.cs

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+namespace TaxBaik.Web.Services.AdminClients;
+
+using System.Text.Json;
+using TaxBaik.Domain.Entities;
+
+public interface IContractBrowserClient
+{
+    Task<List<Contract>> GetAllAsync(CancellationToken ct = default);
+    Task<Contract?> GetByIdAsync(int id, CancellationToken ct = default);
+    Task<List<Contract>> GetByClientIdAsync(int clientId, CancellationToken ct = default);
+    Task<List<Contract>> GetActiveContractsAsync(CancellationToken ct = default);
+    Task<List<Contract>> GetExpiringContractsAsync(int daysAhead = 30, CancellationToken ct = default);
+    Task<decimal> GetMonthlyRecurringRevenueAsync(CancellationToken ct = default);
+    Task<int> CreateAsync(int clientId, string contractNumber, string serviceType, DateTime startDate,
+        decimal? monthlyFee = null, decimal? totalAmount = null, CancellationToken ct = default);
+    Task DeleteAsync(int id, CancellationToken ct = default);
+}
+
+public class ContractBrowserClient(HttpClient httpClient, ITokenStore tokenStore, ILogger<ContractBrowserClient> logger)
+    : IContractBrowserClient
+{
+    private const string BaseUrl = "/api/contract";
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(tokenStore.AccessToken))
+            httpClient.DefaultRequestHeaders.Authorization = new("Bearer", tokenStore.AccessToken);
+        else
+            httpClient.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<List<Contract>> GetAllAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<Contract>>($"{BaseUrl}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get contracts");
+            return [];
+        }
+    }
+
+    public async Task<Contract?> GetByIdAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<Contract>($"{BaseUrl}/{id}", ct);
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get contract {Id}", id);
+            return null;
+        }
+    }
+
+    public async Task<List<Contract>> GetByClientIdAsync(int clientId, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<Contract>>($"{BaseUrl}/client/{clientId}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get contracts for client {ClientId}", clientId);
+            return [];
+        }
+    }
+
+    public async Task<List<Contract>> GetActiveContractsAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.GetFromJsonAsync<JsonElement>($"{BaseUrl}/active", ct);
+            if (response.TryGetProperty("data", out var data))
+                return System.Text.Json.JsonSerializer.Deserialize<List<Contract>>(data.GetRawText()) ?? [];
+            return [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get active contracts");
+            return [];
+        }
+    }
+
+    public async Task<List<Contract>> GetExpiringContractsAsync(int daysAhead = 30, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.GetFromJsonAsync<JsonElement>($"{BaseUrl}/expiring?daysAhead={daysAhead}", ct);
+            if (response.TryGetProperty("data", out var data))
+                return System.Text.Json.JsonSerializer.Deserialize<List<Contract>>(data.GetRawText()) ?? [];
+            return [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get expiring contracts");
+            return [];
+        }
+    }
+
+    public async Task<decimal> GetMonthlyRecurringRevenueAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.GetFromJsonAsync<JsonElement>($"{BaseUrl}/mrr", ct);
+            if (response.TryGetProperty("mrr", out var mrrValue))
+                return System.Text.Json.JsonSerializer.Deserialize<decimal>(mrrValue.GetRawText());
+            return 0;
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get MRR");
+            return 0;
+        }
+    }
+
+    public async Task<int> CreateAsync(int clientId, string contractNumber, string serviceType, DateTime startDate,
+        decimal? monthlyFee = null, decimal? totalAmount = null, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var request = new { clientId, contractNumber, serviceType, startDate, monthlyFee, totalAmount };
+            var response = await httpClient.PostAsJsonAsync(BaseUrl, request, ct);
+            response.EnsureSuccessStatusCode();
+            var result = await response.Content.ReadFromJsonAsync<JsonElement>(cancellationToken: ct);
+            return result.TryGetProperty("id", out var idProp) ? idProp.GetInt32() : 0;
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to create contract");
+            return 0;
+        }
+    }
+
+    public async Task DeleteAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.DeleteAsync($"{BaseUrl}/{id}", ct);
+            response.EnsureSuccessStatusCode();
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to delete contract {Id}", id);
+        }
+    }
+}

TaxBaik.Web.Client/Services/AdminClients/IRevenueTrackingBrowserClient.cs

@@ -0,0 +1,159 @@
+namespace TaxBaik.Web.Services.AdminClients;
+
+using System.Text.Json;
+using TaxBaik.Domain.Entities;
+
+public interface IRevenueTrackingBrowserClient
+{
+    Task<List<RevenueTracking>> GetAllAsync(CancellationToken ct = default);
+    Task<List<RevenueTracking>> GetByClientIdAsync(int clientId, CancellationToken ct = default);
+    Task<List<RevenueTracking>> GetPendingPaymentsAsync(CancellationToken ct = default);
+    Task<List<RevenueTracking>> GetMonthlyRevenueAsync(int year, int month, CancellationToken ct = default);
+    Task<decimal> GetTotalRevenueAsync(DateTime startDate, DateTime endDate, CancellationToken ct = default);
+    Task<int> CreateAsync(int clientId, string invoiceNumber, DateTime invoiceDate, decimal amount,
+        string? serviceType = null, DateTime? dueDate = null, CancellationToken ct = default);
+    Task MarkPaidAsync(int id, DateTime paymentDate, CancellationToken ct = default);
+    Task DeleteAsync(int id, CancellationToken ct = default);
+}
+
+public class RevenueTrackingBrowserClient(HttpClient httpClient, ITokenStore tokenStore, ILogger<RevenueTrackingBrowserClient> logger)
+    : IRevenueTrackingBrowserClient
+{
+    private const string BaseUrl = "/api/revenuetracking";
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(tokenStore.AccessToken))
+            httpClient.DefaultRequestHeaders.Authorization = new("Bearer", tokenStore.AccessToken);
+        else
+            httpClient.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<List<RevenueTracking>> GetAllAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<RevenueTracking>>($"{BaseUrl}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get revenue tracking");
+            return [];
+        }
+    }
+
+    public async Task<List<RevenueTracking>> GetByClientIdAsync(int clientId, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<RevenueTracking>>($"{BaseUrl}/client/{clientId}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get revenue for client {ClientId}", clientId);
+            return [];
+        }
+    }
+
+    public async Task<List<RevenueTracking>> GetPendingPaymentsAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.GetFromJsonAsync<JsonElement>($"{BaseUrl}/pending", ct);
+            if (response.TryGetProperty("data", out var data))
+                return System.Text.Json.JsonSerializer.Deserialize<List<RevenueTracking>>(data.GetRawText()) ?? [];
+            return [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get pending payments");
+            return [];
+        }
+    }
+
+    public async Task<List<RevenueTracking>> GetMonthlyRevenueAsync(int year, int month, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.GetFromJsonAsync<JsonElement>($"{BaseUrl}/monthly?year={year}&month={month}", ct);
+            if (response.TryGetProperty("data", out var data))
+                return System.Text.Json.JsonSerializer.Deserialize<List<RevenueTracking>>(data.GetRawText()) ?? [];
+            return [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get monthly revenue {Year}-{Month}", year, month);
+            return [];
+        }
+    }
+
+    public async Task<decimal> GetTotalRevenueAsync(DateTime startDate, DateTime endDate, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.GetFromJsonAsync<JsonElement>(
+                $"{BaseUrl}/total?startDate={startDate:yyyy-MM-dd}&endDate={endDate:yyyy-MM-dd}", ct);
+            if (response.TryGetProperty("total", out var totalValue))
+                return System.Text.Json.JsonSerializer.Deserialize<decimal>(totalValue.GetRawText());
+            return 0;
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get total revenue");
+            return 0;
+        }
+    }
+
+    public async Task<int> CreateAsync(int clientId, string invoiceNumber, DateTime invoiceDate, decimal amount,
+        string? serviceType = null, DateTime? dueDate = null, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var request = new { clientId, invoiceNumber, invoiceDate, amount, serviceType, dueDate };
+            var response = await httpClient.PostAsJsonAsync(BaseUrl, request, ct);
+            response.EnsureSuccessStatusCode();
+            var result = await response.Content.ReadFromJsonAsync<JsonElement>(cancellationToken: ct);
+            return result.TryGetProperty("id", out var idProp) ? idProp.GetInt32() : 0;
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to create revenue tracking");
+            return 0;
+        }
+    }
+
+    public async Task MarkPaidAsync(int id, DateTime paymentDate, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var request = new { paymentDate };
+            var response = await httpClient.PutAsJsonAsync($"{BaseUrl}/{id}/paid", request, ct);
+            response.EnsureSuccessStatusCode();
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to mark payment {Id}", id);
+        }
+    }
+
+    public async Task DeleteAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.DeleteAsync($"{BaseUrl}/{id}", ct);
+            response.EnsureSuccessStatusCode();
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to delete revenue tracking {Id}", id);
+        }
+    }
+}

TaxBaik.Web.Client/Services/AdminClients/ITaxFilingScheduleBrowserClient.cs

@@ -0,0 +1,136 @@
+namespace TaxBaik.Web.Services.AdminClients;
+
+using System.Text.Json;
+using TaxBaik.Domain.Entities;
+
+public interface ITaxFilingScheduleBrowserClient
+{
+    Task<List<TaxFilingSchedule>> GetAllAsync(CancellationToken ct = default);
+    Task<TaxFilingSchedule?> GetByIdAsync(int id, CancellationToken ct = default);
+    Task<List<TaxFilingSchedule>> GetByClientIdAsync(int clientId, CancellationToken ct = default);
+    Task<List<TaxFilingSchedule>> GetUpcomingDuesAsync(int daysAhead = 30, CancellationToken ct = default);
+    Task<int> CreateAsync(int clientId, string filingType, DateTime dueDate, int filingYear,
+        int? assignedTo = null, CancellationToken ct = default);
+    Task MarkCompletedAsync(int id, CancellationToken ct = default);
+    Task DeleteAsync(int id, CancellationToken ct = default);
+}
+
+public class TaxFilingScheduleBrowserClient(HttpClient httpClient, ITokenStore tokenStore, ILogger<TaxFilingScheduleBrowserClient> logger)
+    : ITaxFilingScheduleBrowserClient
+{
+    private const string BaseUrl = "/api/taxfilingschedule";
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(tokenStore.AccessToken))
+            httpClient.DefaultRequestHeaders.Authorization = new("Bearer", tokenStore.AccessToken);
+        else
+            httpClient.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<List<TaxFilingSchedule>> GetAllAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<TaxFilingSchedule>>($"{BaseUrl}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get tax filing schedules");
+            return [];
+        }
+    }
+
+    public async Task<TaxFilingSchedule?> GetByIdAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<TaxFilingSchedule>($"{BaseUrl}/{id}", ct);
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get tax filing schedule {Id}", id);
+            return null;
+        }
+    }
+
+    public async Task<List<TaxFilingSchedule>> GetByClientIdAsync(int clientId, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<TaxFilingSchedule>>($"{BaseUrl}/client/{clientId}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get filing schedules for client {ClientId}", clientId);
+            return [];
+        }
+    }
+
+    public async Task<List<TaxFilingSchedule>> GetUpcomingDuesAsync(int daysAhead = 30, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.GetFromJsonAsync<JsonElement>($"{BaseUrl}/upcoming?daysAhead={daysAhead}", ct);
+            if (response.TryGetProperty("data", out var data))
+                return System.Text.Json.JsonSerializer.Deserialize<List<TaxFilingSchedule>>(data.GetRawText()) ?? [];
+            return [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get upcoming filings");
+            return [];
+        }
+    }
+
+    public async Task<int> CreateAsync(int clientId, string filingType, DateTime dueDate, int filingYear,
+        int? assignedTo = null, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var request = new { clientId, filingType, dueDate, filingYear, assignedTo };
+            var response = await httpClient.PostAsJsonAsync(BaseUrl, request, ct);
+            response.EnsureSuccessStatusCode();
+            var result = await response.Content.ReadFromJsonAsync<JsonElement>(cancellationToken: ct);
+            return result.TryGetProperty("id", out var idProp) ? idProp.GetInt32() : 0;
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to create tax filing schedule");
+            return 0;
+        }
+    }
+
+    public async Task MarkCompletedAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.PutAsJsonAsync($"{BaseUrl}/{id}/complete", new { }, ct);
+            response.EnsureSuccessStatusCode();
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to mark filing as completed {Id}", id);
+        }
+    }
+
+    public async Task DeleteAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.DeleteAsync($"{BaseUrl}/{id}", ct);
+            response.EnsureSuccessStatusCode();
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to delete tax filing schedule {Id}", id);
+        }
+    }
+}

TaxBaik.Web.Client/Services/AdminClients/ITaxProfileBrowserClient.cs

@@ -0,0 +1,156 @@
+namespace TaxBaik.Web.Services.AdminClients;
+
+using System.Text.Json;
+using TaxBaik.Domain.Entities;
+
+public interface ITaxProfileBrowserClient
+{
+    Task<List<TaxProfile>> GetAllAsync(CancellationToken ct = default);
+    Task<TaxProfile?> GetByIdAsync(int id, CancellationToken ct = default);
+    Task<List<TaxProfile>> GetByClientIdAsync(int clientId, CancellationToken ct = default);
+    Task<List<TaxProfile>> GetHighRiskProfilesAsync(CancellationToken ct = default);
+    Task<List<TaxProfile>> GetUpcomingFilingDuesAsync(int daysAhead = 30, CancellationToken ct = default);
+    Task<int> CreateAsync(int clientId, string businessType, string? businessRegistration = null,
+        string? accountingMethod = null, DateTime? establishmentDate = null, CancellationToken ct = default);
+    Task UpdateAsync(int id, string? businessType = null, string? accountingMethod = null,
+        DateTime? nextFilingDueDate = null, string? taxRiskLevel = null, CancellationToken ct = default);
+    Task DeleteAsync(int id, CancellationToken ct = default);
+}
+
+public class TaxProfileBrowserClient(HttpClient httpClient, ITokenStore tokenStore, ILogger<TaxProfileBrowserClient> logger) : ITaxProfileBrowserClient
+{
+    private const string BaseUrl = "/api/taxprofile";
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(tokenStore.AccessToken))
+            httpClient.DefaultRequestHeaders.Authorization = new("Bearer", tokenStore.AccessToken);
+        else
+            httpClient.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<List<TaxProfile>> GetAllAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<TaxProfile>>($"{BaseUrl}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get tax profiles");
+            return [];
+        }
+    }
+
+    public async Task<TaxProfile?> GetByIdAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<TaxProfile>($"{BaseUrl}/{id}", ct);
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get tax profile {Id}", id);
+            return null;
+        }
+    }
+
+    public async Task<List<TaxProfile>> GetByClientIdAsync(int clientId, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await httpClient.GetFromJsonAsync<List<TaxProfile>>($"{BaseUrl}/client/{clientId}", ct) ?? [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get tax profiles for client {ClientId}", clientId);
+            return [];
+        }
+    }
+
+    public async Task<List<TaxProfile>> GetHighRiskProfilesAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.GetFromJsonAsync<JsonElement>($"{BaseUrl}/high-risk", ct);
+            if (response.TryGetProperty("data", out var data))
+                return System.Text.Json.JsonSerializer.Deserialize<List<TaxProfile>>(data.GetRawText()) ?? [];
+            return [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get high-risk profiles");
+            return [];
+        }
+    }
+
+    public async Task<List<TaxProfile>> GetUpcomingFilingDuesAsync(int daysAhead = 30, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.GetFromJsonAsync<JsonElement>($"{BaseUrl}/upcoming-filings?daysAhead={daysAhead}", ct);
+            if (response.TryGetProperty("data", out var data))
+                return System.Text.Json.JsonSerializer.Deserialize<List<TaxProfile>>(data.GetRawText()) ?? [];
+            return [];
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to get upcoming filings");
+            return [];
+        }
+    }
+
+    public async Task<int> CreateAsync(int clientId, string businessType, string? businessRegistration = null,
+        string? accountingMethod = null, DateTime? establishmentDate = null, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var request = new { clientId, businessType, businessRegistration, accountingMethod, establishmentDate };
+            var response = await httpClient.PostAsJsonAsync(BaseUrl, request, ct);
+            response.EnsureSuccessStatusCode();
+            var result = await response.Content.ReadFromJsonAsync<JsonElement>(cancellationToken: ct);
+            return result.TryGetProperty("id", out var idProp) ? idProp.GetInt32() : 0;
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to create tax profile");
+            return 0;
+        }
+    }
+
+    public async Task UpdateAsync(int id, string? businessType = null, string? accountingMethod = null,
+        DateTime? nextFilingDueDate = null, string? taxRiskLevel = null, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var request = new { businessType, accountingMethod, nextFilingDueDate, taxRiskLevel };
+            var response = await httpClient.PutAsJsonAsync($"{BaseUrl}/{id}", request, ct);
+            response.EnsureSuccessStatusCode();
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to update tax profile {Id}", id);
+        }
+    }
+
+    public async Task DeleteAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await httpClient.DeleteAsync($"{BaseUrl}/{id}", ct);
+            response.EnsureSuccessStatusCode();
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to delete tax profile {Id}", id);
+        }
+    }
+}

TaxBaik.Web.Client/Services/AdminDashboardClient.cs

@@ -0,0 +1,119 @@
+using System.Net.Http;
+using System.Net.Http.Json;
+using TaxBaik.Application.Services;
+using TaxBaik.Domain.Entities;
+
+namespace TaxBaik.Web.Services;
+
+/// <summary>
+/// Admin Dashboard API Client
+/// SOLID: Single Responsibility - Dashboard API 호출만 담당
+/// Dependency Inversion - 추상화된 인터페이스 사용
+/// </summary>
+public interface IAdminDashboardClient
+{
+    Task<AdminDashboardSummary> GetSummaryAsync(CancellationToken ct = default);
+    Task<IEnumerable<TaxFiling>> GetUpcomingFilingsAsync(int days = 30, CancellationToken ct = default);
+    Task<IEnumerable<Inquiry>> GetRecentInquiriesAsync(int limit = 10, CancellationToken ct = default);
+    Task<object> GetMonthlyStatsAsync(string? month = null, CancellationToken ct = default);
+}
+
+public class AdminDashboardClient : IAdminDashboardClient
+{
+    private readonly HttpClient _http;
+    private readonly ILogger<AdminDashboardClient> _logger;
+    private readonly ITokenStore _tokenStore;
+
+    public AdminDashboardClient(HttpClient http, ILogger<AdminDashboardClient> logger, ITokenStore tokenStore)
+    {
+        _http = http;
+        _logger = logger;
+        _tokenStore = tokenStore;
+    }
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(_tokenStore.AccessToken))
+            _http.DefaultRequestHeaders.Authorization = new("Bearer", _tokenStore.AccessToken);
+        else
+            _http.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<AdminDashboardSummary> GetSummaryAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var result = await _http.GetFromJsonAsync<AdminDashboardSummary>(
+                "admin-dashboard/summary", cancellationToken: ct);
+            return result ?? new(0, 0, 0, 0, []);
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch dashboard summary");
+            throw;
+        }
+    }
+
+    public async Task<IEnumerable<TaxFiling>> GetUpcomingFilingsAsync(int days = 30, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var result = await _http.GetFromJsonAsync<ApiResponse<TaxFiling>>(
+                $"admin-dashboard/upcoming-filings?days={days}", cancellationToken: ct);
+            return result?.Data ?? [];
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch upcoming filings");
+            throw;
+        }
+    }
+
+    public async Task<IEnumerable<Inquiry>> GetRecentInquiriesAsync(int limit = 10, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var result = await _http.GetFromJsonAsync<ApiResponse<Inquiry>>(
+                $"admin-dashboard/recent-inquiries?limit={limit}", cancellationToken: ct);
+            return result?.Data ?? [];
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch recent inquiries");
+            throw;
+        }
+    }
+
+    public async Task<object> GetMonthlyStatsAsync(string? month = null, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var url = "admin-dashboard/monthly-stats";
+            if (!string.IsNullOrEmpty(month))
+                url += $"?month={month}";
+
+            var result = await _http.GetFromJsonAsync<object>(url, cancellationToken: ct);
+            return result ?? new();
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch monthly stats");
+            throw;
+        }
+    }
+}
+
+/// <summary>
+/// API Response wrapper
+/// </summary>
+internal class ApiResponse<T>
+{
+    public IEnumerable<T>? Data { get; set; }
+    public int Total { get; set; }
+    public int Page { get; set; }
+    public int PageSize { get; set; }
+}

TaxBaik.Web.Client/Services/AnnouncementBrowserClient.cs

@@ -0,0 +1,126 @@
+namespace TaxBaik.Web.Services;
+
+using System.Net.Http;
+using System.Net.Http.Json;
+using TaxBaik.Application.DTOs;
+using TaxBaik.Domain.Entities;
+
+public interface IAnnouncementBrowserClient
+{
+    Task<IEnumerable<Announcement>> GetAllAsync(CancellationToken ct = default);
+    Task<Announcement?> GetByIdAsync(int id, CancellationToken ct = default);
+    Task<Announcement?> CreateAsync(AnnouncementDto dto, CancellationToken ct = default);
+    Task<Announcement?> UpdateAsync(int id, AnnouncementDto dto, CancellationToken ct = default);
+    Task<bool> DeleteAsync(int id, CancellationToken ct = default);
+}
+
+public class AnnouncementBrowserClient : IAnnouncementBrowserClient
+{
+    private readonly HttpClient _http;
+    private readonly ILogger<AnnouncementBrowserClient> _logger;
+    private readonly ITokenStore _tokenStore;
+
+    public AnnouncementBrowserClient(HttpClient http, ILogger<AnnouncementBrowserClient> logger, ITokenStore tokenStore)
+    {
+        _http = http;
+        _logger = logger;
+        _tokenStore = tokenStore;
+    }
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(_tokenStore.AccessToken))
+            _http.DefaultRequestHeaders.Authorization = new("Bearer", _tokenStore.AccessToken);
+        else
+            _http.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<IEnumerable<Announcement>> GetAllAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var result = await _http.GetFromJsonAsync<AnnouncementListResponse>("announcement", cancellationToken: ct);
+            return result?.Data ?? [];
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch announcements");
+            throw;
+        }
+    }
+
+    public async Task<Announcement?> GetByIdAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await _http.GetFromJsonAsync<Announcement>($"announcement/{id}", cancellationToken: ct);
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch announcement {AnnouncementId}", id);
+            throw;
+        }
+    }
+
+    public async Task<Announcement?> CreateAsync(AnnouncementDto dto, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.PostAsJsonAsync("announcement", dto, cancellationToken: ct);
+            if (!response.IsSuccessStatusCode) return null;
+
+            var content = await response.Content.ReadAsStringAsync(ct);
+            return System.Text.Json.JsonSerializer.Deserialize<Announcement>(
+                content,
+                new System.Text.Json.JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to create announcement");
+            throw;
+        }
+    }
+
+    public async Task<Announcement?> UpdateAsync(int id, AnnouncementDto dto, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.PutAsJsonAsync($"announcement/{id}", dto, cancellationToken: ct);
+            if (!response.IsSuccessStatusCode) return null;
+
+            var content = await response.Content.ReadAsStringAsync(ct);
+            return System.Text.Json.JsonSerializer.Deserialize<Announcement>(
+                content,
+                new System.Text.Json.JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to update announcement {AnnouncementId}", id);
+            throw;
+        }
+    }
+
+    public async Task<bool> DeleteAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.DeleteAsync($"announcement/{id}", cancellationToken: ct);
+            return response.IsSuccessStatusCode;
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to delete announcement {AnnouncementId}", id);
+            throw;
+        }
+    }
+
+    private class AnnouncementListResponse
+    {
+        public List<Announcement> Data { get; set; } = [];
+    }
+}

TaxBaik.Web.Client/Services/ApiClient.cs

@@ -0,0 +1,110 @@
+namespace TaxBaik.Web.Services;
+
+using Microsoft.AspNetCore.Components;
+using System.Text.Json;
+
+public interface IApiClient
+{
+    Task<T?> GetAsync<T>(string endpoint);
+    Task<T?> PostAsync<T>(string endpoint, object data);
+    Task<T?> PutAsync<T>(string endpoint, object data);
+    Task DeleteAsync(string endpoint);
+    Task SetAuthToken(string? token);
+}
+
+public class ApiClient : IApiClient
+{
+    private readonly HttpClient _httpClient;
+    private readonly NavigationManager _navigationManager;
+    private string? _authToken;
+
+    public ApiClient(HttpClient httpClient, NavigationManager navigationManager)
+    {
+        _httpClient = httpClient;
+        _navigationManager = navigationManager;
+    }
+
+    public async Task SetAuthToken(string? token)
+    {
+        _authToken = token;
+        if (token != null)
+            _httpClient.DefaultRequestHeaders.Authorization = new("Bearer", token);
+        else
+            _httpClient.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<T?> GetAsync<T>(string endpoint)
+    {
+        try
+        {
+            var response = await _httpClient.GetAsync(BuildApiUri(endpoint));
+            if (!response.IsSuccessStatusCode)
+                return default;
+
+            var content = await response.Content.ReadAsStringAsync();
+            return JsonSerializer.Deserialize<T>(content, new JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+        }
+        catch
+        {
+            return default;
+        }
+    }
+
+    public async Task<T?> PostAsync<T>(string endpoint, object data)
+    {
+        try
+        {
+            var json = JsonSerializer.Serialize(data);
+            var content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");
+            var response = await _httpClient.PostAsync(BuildApiUri(endpoint), content);
+
+            if (!response.IsSuccessStatusCode)
+                return default;
+
+            var responseContent = await response.Content.ReadAsStringAsync();
+            return JsonSerializer.Deserialize<T>(responseContent, new JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+        }
+        catch
+        {
+            return default;
+        }
+    }
+
+    public async Task<T?> PutAsync<T>(string endpoint, object data)
+    {
+        try
+        {
+            var json = JsonSerializer.Serialize(data);
+            var content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");
+            var response = await _httpClient.PutAsync(BuildApiUri(endpoint), content);
+
+            if (!response.IsSuccessStatusCode)
+                return default;
+
+            var responseContent = await response.Content.ReadAsStringAsync();
+            return JsonSerializer.Deserialize<T>(responseContent, new JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+        }
+        catch
+        {
+            return default;
+        }
+    }
+
+    public async Task DeleteAsync(string endpoint)
+    {
+        try
+        {
+            await _httpClient.DeleteAsync(BuildApiUri(endpoint));
+        }
+        catch
+        {
+            // Ignore
+        }
+    }
+
+    private Uri BuildApiUri(string endpoint)
+    {
+        var relative = $"api/{endpoint.TrimStart('/')}";
+        return new Uri(new Uri(_navigationManager.BaseUri), relative);
+    }
+}

TaxBaik.Web.Client/Services/ClientBrowserClient.cs

@@ -0,0 +1,141 @@
+namespace TaxBaik.Web.Services;
+
+using System.Net.Http;
+using System.Net.Http.Json;
+using TaxBaik.Application.DTOs;
+using TaxBaik.Domain.Entities;
+
+/// <summary>
+/// Client API Client for Admin Blazor
+/// SOLID: Single Responsibility - Client API calls only
+/// </summary>
+public interface IClientBrowserClient
+{
+    Task<(IEnumerable<Client> Items, int Total)> GetPagedAsync(
+        int page = 1, int pageSize = 20, string? status = null, string? search = null, CancellationToken ct = default);
+    Task<Client?> GetByIdAsync(int id, CancellationToken ct = default);
+    Task<Client?> CreateAsync(CreateClientDto dto, CancellationToken ct = default);
+    Task<Client?> UpdateAsync(int id, CreateClientDto dto, CancellationToken ct = default);
+    Task<bool> DeleteAsync(int id, CancellationToken ct = default);
+}
+
+public class ClientBrowserClient : IClientBrowserClient
+{
+    private readonly HttpClient _http;
+    private readonly ILogger<ClientBrowserClient> _logger;
+    private readonly ITokenStore _tokenStore;
+
+    public ClientBrowserClient(HttpClient http, ILogger<ClientBrowserClient> logger, ITokenStore tokenStore)
+    {
+        _http = http;
+        _logger = logger;
+        _tokenStore = tokenStore;
+    }
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(_tokenStore.AccessToken))
+            _http.DefaultRequestHeaders.Authorization = new("Bearer", _tokenStore.AccessToken);
+        else
+            _http.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<(IEnumerable<Client> Items, int Total)> GetPagedAsync(
+        int page = 1, int pageSize = 20, string? status = null, string? search = null, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var query = $"client?page={page}&pageSize={pageSize}";
+            if (!string.IsNullOrEmpty(status))
+                query += $"&status={status}";
+            if (!string.IsNullOrEmpty(search))
+                query += $"&search={Uri.EscapeDataString(search)}";
+
+            var result = await _http.GetFromJsonAsync<ClientPagedResponse>(query, cancellationToken: ct);
+            return result != null ? (result.Data, result.Total) : ([], 0);
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch clients");
+            throw;
+        }
+    }
+
+    public async Task<Client?> GetByIdAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await _http.GetFromJsonAsync<Client>($"client/{id}", cancellationToken: ct);
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch client {ClientId}", id);
+            throw;
+        }
+    }
+
+    public async Task<Client?> CreateAsync(CreateClientDto dto, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.PostAsJsonAsync("client", dto, cancellationToken: ct);
+            if (!response.IsSuccessStatusCode)
+                return null;
+
+            var content = await response.Content.ReadAsStringAsync(ct);
+            return System.Text.Json.JsonSerializer.Deserialize<Client>(
+                content,
+                new System.Text.Json.JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to create client");
+            throw;
+        }
+    }
+
+    public async Task<Client?> UpdateAsync(int id, CreateClientDto dto, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.PutAsJsonAsync($"client/{id}", dto, cancellationToken: ct);
+            if (!response.IsSuccessStatusCode)
+                return null;
+
+            var content = await response.Content.ReadAsStringAsync(ct);
+            return System.Text.Json.JsonSerializer.Deserialize<Client>(
+                content,
+                new System.Text.Json.JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to update client {ClientId}", id);
+            throw;
+        }
+    }
+
+    public async Task<bool> DeleteAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.DeleteAsync($"client/{id}", cancellationToken: ct);
+            return response.IsSuccessStatusCode;
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to delete client {ClientId}", id);
+            throw;
+        }
+    }
+
+    private class ClientPagedResponse
+    {
+        public List<Client> Data { get; set; } = [];
+        public int Total { get; set; }
+    }
+}

TaxBaik.Web.Client/Services/CustomAuthenticationStateProvider.cs

@@ -0,0 +1,192 @@
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+using Microsoft.AspNetCore.Components.Authorization;
+using TaxBaik.Application.Services;
+
+namespace TaxBaik.Web.Services;
+
+public class CustomAuthenticationStateProvider : AuthenticationStateProvider
+{
+    private readonly ILocalStorageService _localStorage;
+    private readonly ITokenStore _tokenStore;
+    private readonly IApiClient _apiClient;
+    private readonly ILogger<CustomAuthenticationStateProvider> _logger;
+
+    public CustomAuthenticationStateProvider(
+        ILocalStorageService localStorage,
+        ITokenStore tokenStore,
+        IApiClient apiClient,
+        ILogger<CustomAuthenticationStateProvider> logger)
+    {
+        _localStorage = localStorage;
+        _tokenStore = tokenStore;
+        _apiClient = apiClient;
+        _logger = logger;
+    }
+
+    public override async Task<AuthenticationState> GetAuthenticationStateAsync()
+    {
+        try
+        {
+            var accessToken = _tokenStore.AccessToken;
+
+            // TokenStore가 비어있으면 localStorage에서 복원 (페이지 리로드 후)
+            if (string.IsNullOrEmpty(accessToken))
+            {
+                var storedToken = await _localStorage.GetItemAsStringAsync("accessToken");
+                if (!string.IsNullOrEmpty(storedToken))
+                {
+                    var refreshToken = await _localStorage.GetItemAsStringAsync("refreshToken");
+                    var ticksStr = await _localStorage.GetItemAsStringAsync("tokenExpiry");
+                    if (long.TryParse(ticksStr, out var ticks))
+                    {
+                        _tokenStore.AccessToken = storedToken;
+                        _tokenStore.RefreshToken = refreshToken;
+                        _tokenStore.TokenExpiryTicks = ticks;
+                        accessToken = storedToken;
+                    }
+                }
+            }
+
+            if (string.IsNullOrEmpty(_tokenStore.AccessToken))
+            {
+                return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
+            }
+
+            // 토큰이 만료되면 로그아웃
+            if (_tokenStore.IsAccessTokenExpired())
+            {
+                _logger.LogWarning("Access token 만료됨 - 자동 로그아웃");
+                await LogoutAsync();
+                return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
+            }
+
+            // 토큰이 5분 이내로 만료되면 자동 갱신 시도 (사용자 경험 향상)
+            if (!string.IsNullOrEmpty(_tokenStore.RefreshToken) && ShouldRefreshToken())
+            {
+                _logger.LogInformation("토큰 만료 5분 전 - 자동 갱신 시작");
+                var request = new { RefreshToken = _tokenStore.RefreshToken };
+                var newTokenPair = await _apiClient.PostAsync<WasmAuthTokenPair>("auth/refresh", request);
+                if (newTokenPair != null && !string.IsNullOrEmpty(newTokenPair.AccessToken))
+                {
+                    await LoginAsync(newTokenPair.AccessToken, newTokenPair.RefreshToken, newTokenPair.ExpiresIn);
+                    _logger.LogInformation("토큰 자동 갱신 성공");
+                    accessToken = newTokenPair.AccessToken;
+                }
+                else
+                {
+                    _logger.LogWarning("토큰 자동 갱신 실패 - 로그아웃");
+                    await LogoutAsync();
+                    return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
+                }
+            }
+
+            var principal = ValidateTokenWithoutDb(accessToken ?? string.Empty);
+            if (principal == null)
+            {
+                await LogoutAsync();
+                return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
+            }
+
+            return new AuthenticationState(principal);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "인증 상태 조회 중 오류 발생");
+            return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
+        }
+    }
+
+    private ClaimsPrincipal? ValidateTokenWithoutDb(string token)
+    {
+        try
+        {
+            var handler = new JwtSecurityTokenHandler();
+            var jwtToken = handler.ReadJwtToken(token);
+            var identity = new ClaimsIdentity(jwtToken.Claims, "jwt");
+            return new ClaimsPrincipal(identity);
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+
+    public async Task LoginAsync(string accessToken, string refreshToken, int expiresIn)
+    {
+        var tokenExpiryTicks = DateTime.UtcNow.AddSeconds(expiresIn).Ticks;
+
+        // TokenStore에 저장 (DelegatingHandler에서 사용)
+        _tokenStore.AccessToken = accessToken;
+        _tokenStore.RefreshToken = refreshToken;
+        _tokenStore.TokenExpiryTicks = tokenExpiryTicks;
+
+        // localStorage에도 저장 (페이지 리로드 후 복원)
+        await _localStorage.SetItemAsStringAsync("accessToken", accessToken);
+        await _localStorage.SetItemAsStringAsync("refreshToken", refreshToken);
+        await _localStorage.SetItemAsStringAsync("tokenExpiry", tokenExpiryTicks.ToString());
+
+        NotifyAuthenticationStateChanged(GetAuthenticationStateAsync());
+    }
+
+    private bool ShouldRefreshToken()
+    {
+        // 토큰이 5분 이내로 만료되면 갱신 (300초 = 5분)
+        if (!_tokenStore.TokenExpiryTicks.HasValue || _tokenStore.TokenExpiryTicks.Value <= 0)
+            return false;
+
+        const int refreshThresholdSeconds = 300;
+        try
+        {
+            var expiryTime = new DateTime(_tokenStore.TokenExpiryTicks.Value, DateTimeKind.Utc);
+            var timeUntilExpiry = expiryTime - DateTime.UtcNow;
+            return timeUntilExpiry.TotalSeconds <= refreshThresholdSeconds && timeUntilExpiry.TotalSeconds > 0;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    public async Task LogoutAsync()
+    {
+        // TokenStore 초기화
+        _tokenStore.Clear();
+
+        // localStorage 초기화
+        await _localStorage.RemoveItemAsync("accessToken");
+        await _localStorage.RemoveItemAsync("refreshToken");
+        await _localStorage.RemoveItemAsync("tokenExpiry");
+
+        NotifyAuthenticationStateChanged(GetAuthenticationStateAsync());
+    }
+
+    private bool IsTokenExpired(string token)
+    {
+        try
+        {
+            var handler = new JwtSecurityTokenHandler();
+            var jwtToken = handler.ReadJwtToken(token);
+            return jwtToken.ValidTo < DateTime.UtcNow;
+        }
+        catch
+        {
+            return true;
+        }
+    }
+}
+
+public class WasmAuthTokenPair
+{
+    public WasmAuthTokenPair() { }
+    public WasmAuthTokenPair(string accessToken, string refreshToken, int expiresIn)
+    {
+        AccessToken = accessToken;
+        RefreshToken = refreshToken;
+        ExpiresIn = expiresIn;
+    }
+    public string AccessToken { get; set; } = "";
+    public string RefreshToken { get; set; } = "";
+    public int ExpiresIn { get; set; }
+}

TaxBaik.Web.Client/Services/FaqBrowserClient.cs

@@ -0,0 +1,125 @@
+namespace TaxBaik.Web.Services;
+
+using System.Net.Http;
+using System.Net.Http.Json;
+using TaxBaik.Domain.Entities;
+
+public interface IFaqBrowserClient
+{
+    Task<IEnumerable<Faq>> GetAllAsync(CancellationToken ct = default);
+    Task<Faq?> GetByIdAsync(int id, CancellationToken ct = default);
+    Task<Faq?> CreateAsync(Faq faq, CancellationToken ct = default);
+    Task<Faq?> UpdateAsync(int id, Faq faq, CancellationToken ct = default);
+    Task<bool> DeleteAsync(int id, CancellationToken ct = default);
+}
+
+public class FaqBrowserClient : IFaqBrowserClient
+{
+    private readonly HttpClient _http;
+    private readonly ILogger<FaqBrowserClient> _logger;
+    private readonly ITokenStore _tokenStore;
+
+    public FaqBrowserClient(HttpClient http, ILogger<FaqBrowserClient> logger, ITokenStore tokenStore)
+    {
+        _http = http;
+        _logger = logger;
+        _tokenStore = tokenStore;
+    }
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(_tokenStore.AccessToken))
+            _http.DefaultRequestHeaders.Authorization = new("Bearer", _tokenStore.AccessToken);
+        else
+            _http.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<IEnumerable<Faq>> GetAllAsync(CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var result = await _http.GetFromJsonAsync<FaqListResponse>("faq", cancellationToken: ct);
+            return result?.Data ?? [];
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch FAQs");
+            throw;
+        }
+    }
+
+    public async Task<Faq?> GetByIdAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await _http.GetFromJsonAsync<Faq>($"faq/{id}", cancellationToken: ct);
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch FAQ {FaqId}", id);
+            throw;
+        }
+    }
+
+    public async Task<Faq?> CreateAsync(Faq faq, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.PostAsJsonAsync("faq", faq, cancellationToken: ct);
+            if (!response.IsSuccessStatusCode) return null;
+
+            var content = await response.Content.ReadAsStringAsync(ct);
+            return System.Text.Json.JsonSerializer.Deserialize<Faq>(
+                content,
+                new System.Text.Json.JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to create FAQ");
+            throw;
+        }
+    }
+
+    public async Task<Faq?> UpdateAsync(int id, Faq faq, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.PutAsJsonAsync($"faq/{id}", faq, cancellationToken: ct);
+            if (!response.IsSuccessStatusCode) return null;
+
+            var content = await response.Content.ReadAsStringAsync(ct);
+            return System.Text.Json.JsonSerializer.Deserialize<Faq>(
+                content,
+                new System.Text.Json.JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to update FAQ {FaqId}", id);
+            throw;
+        }
+    }
+
+    public async Task<bool> DeleteAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.DeleteAsync($"faq/{id}", cancellationToken: ct);
+            return response.IsSuccessStatusCode;
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to delete FAQ {FaqId}", id);
+            throw;
+        }
+    }
+
+    private class FaqListResponse
+    {
+        public List<Faq> Data { get; set; } = [];
+    }
+}

TaxBaik.Web.Client/Services/ILocalStorageService.cs

@@ -0,0 +1,8 @@
+namespace TaxBaik.Web.Services;
+
+public interface ILocalStorageService
+{
+    Task<string?> GetItemAsStringAsync(string key);
+    Task SetItemAsStringAsync(string key, string value);
+    Task RemoveItemAsync(string key);
+}

TaxBaik.Web.Client/Services/ITokenStore.cs

@@ -0,0 +1,39 @@
+namespace TaxBaik.Web.Services;
+
+/// <summary>
+/// Scoped in-memory token store for Blazor Server.
+/// SOLID: Single Responsibility - Token lifecycle management
+/// Avoids JS interop from DelegatingHandler (which runs on non-circuit thread)
+/// </summary>
+public interface ITokenStore
+{
+    string? AccessToken { get; set; }
+    string? RefreshToken { get; set; }
+    long? TokenExpiryTicks { get; set; }
+
+    bool IsAccessTokenExpired();
+    void Clear();
+}
+
+public class TokenStore : ITokenStore
+{
+    public string? AccessToken { get; set; }
+    public string? RefreshToken { get; set; }
+    public long? TokenExpiryTicks { get; set; }
+
+    public bool IsAccessTokenExpired()
+    {
+        if (TokenExpiryTicks == null)
+            return true;
+
+        var expiryTime = new DateTime(TokenExpiryTicks.Value, DateTimeKind.Utc);
+        return expiryTime <= DateTime.UtcNow;
+    }
+
+    public void Clear()
+    {
+        AccessToken = null;
+        RefreshToken = null;
+        TokenExpiryTicks = null;
+    }
+}

TaxBaik.Web.Client/Services/InquiryBrowserClient.cs

@@ -0,0 +1,158 @@
+namespace TaxBaik.Web.Services;
+
+using System.Net.Http;
+using System.Net.Http.Json;
+using TaxBaik.Domain.Entities;
+
+/// <summary>
+/// Inquiry API Client for Admin Blazor
+/// SOLID: Single Responsibility - Inquiry API calls only
+/// Dependency Inversion - abstraction via interface
+/// </summary>
+public interface IInquiryBrowserClient
+{
+    Task<(IEnumerable<Inquiry> Items, int Total)> GetPagedAsync(int page = 1, int pageSize = 20, CancellationToken ct = default);
+    Task<Inquiry?> GetByIdAsync(int id, CancellationToken ct = default);
+    Task<bool> UpdateStatusAsync(int id, string status, CancellationToken ct = default);
+    Task<bool> UpdateAdminMemoAsync(int id, string adminMemo, CancellationToken ct = default);
+    Task<int> ConvertToClientAsync(int id, string name, string phone, string serviceType, CancellationToken ct = default);
+}
+
+public class InquiryBrowserClient : IInquiryBrowserClient
+{
+    private readonly HttpClient _http;
+    private readonly ILogger<InquiryBrowserClient> _logger;
+    private readonly ITokenStore _tokenStore;
+
+    public InquiryBrowserClient(HttpClient http, ILogger<InquiryBrowserClient> logger, ITokenStore tokenStore)
+    {
+        _http = http;
+        _logger = logger;
+        _tokenStore = tokenStore;
+    }
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(_tokenStore.AccessToken))
+            _http.DefaultRequestHeaders.Authorization = new("Bearer", _tokenStore.AccessToken);
+        else
+            _http.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<(IEnumerable<Inquiry> Items, int Total)> GetPagedAsync(
+        int page = 1, int pageSize = 20, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var result = await _http.GetFromJsonAsync<InquiryPagedResponse>(
+                $"inquiry?page={page}&pageSize={pageSize}",
+                cancellationToken: ct);
+
+            return result != null
+                ? (result.Data, result.Total)
+                : ([], 0);
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch inquiries");
+            throw;
+        }
+    }
+
+    public async Task<Inquiry?> GetByIdAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await _http.GetFromJsonAsync<Inquiry>(
+                $"inquiry/{id}",
+                cancellationToken: ct);
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch inquiry {InquiryId}", id);
+            throw;
+        }
+    }
+
+    public async Task<bool> UpdateStatusAsync(int id, string status, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var request = new { status };
+            var response = await _http.PutAsJsonAsync(
+                $"inquiry/{id}/status",
+                request,
+                cancellationToken: ct);
+
+            return response.IsSuccessStatusCode;
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to update inquiry {InquiryId} status", id);
+            throw;
+        }
+    }
+
+    public async Task<bool> UpdateAdminMemoAsync(int id, string adminMemo, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var request = new { adminMemo };
+            var response = await _http.PutAsJsonAsync(
+                $"inquiry/{id}/memo",
+                request,
+                cancellationToken: ct);
+
+            return response.IsSuccessStatusCode;
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to update inquiry {InquiryId} memo", id);
+            throw;
+        }
+    }
+
+    public async Task<int> ConvertToClientAsync(int id, string name, string phone, string serviceType, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.PostAsJsonAsync(
+                $"inquiry/{id}/convert-to-client",
+                new { name, phone, serviceType },
+                cancellationToken: ct);
+
+            if (!response.IsSuccessStatusCode)
+                return 0;
+
+            var content = await response.Content.ReadAsStringAsync(ct);
+            var result = System.Text.Json.JsonSerializer.Deserialize<ConvertToClientResponse>(
+                content,
+                new System.Text.Json.JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+
+            return result?.ClientId ?? 0;
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to convert inquiry {InquiryId} to client", id);
+            throw;
+        }
+    }
+
+    private class InquiryPagedResponse
+    {
+        public List<Inquiry> Data { get; set; } = [];
+        public int Total { get; set; }
+        public int Page { get; set; }
+        public int PageSize { get; set; }
+    }
+
+    private class ConvertToClientResponse
+    {
+        public int ClientId { get; set; }
+    }
+}

TaxBaik.Web.Client/Services/LocalStorageService.cs

@@ -0,0 +1,43 @@
+using Microsoft.JSInterop;
+
+namespace TaxBaik.Web.Services;
+
+public class LocalStorageService : ILocalStorageService
+{
+    private readonly IJSRuntime _jsRuntime;
+
+    public LocalStorageService(IJSRuntime jsRuntime)
+    {
+        _jsRuntime = jsRuntime;
+    }
+
+    public async Task<string?> GetItemAsStringAsync(string key)
+    {
+        try
+        {
+            return await _jsRuntime.InvokeAsync<string>("localStorage.getItem", key);
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    public async Task SetItemAsStringAsync(string key, string value)
+    {
+        try
+        {
+            await _jsRuntime.InvokeVoidAsync("localStorage.setItem", key, value);
+        }
+        catch { }
+    }
+
+    public async Task RemoveItemAsync(string key)
+    {
+        try
+        {
+            await _jsRuntime.InvokeVoidAsync("localStorage.removeItem", key);
+        }
+        catch { }
+    }
+}

TaxBaik.Web.Client/Services/TaxFilingBrowserClient.cs

@@ -0,0 +1,149 @@
+namespace TaxBaik.Web.Services;
+
+using System.Net.Http;
+using System.Net.Http.Json;
+using TaxBaik.Domain.Entities;
+
+/// <summary>
+/// TaxFiling API Client for Admin Blazor
+/// </summary>
+public interface ITaxFilingBrowserClient
+{
+    Task<IEnumerable<TaxFiling>> GetUpcomingAsync(int daysAhead = 30, CancellationToken ct = default);
+    Task<IEnumerable<TaxFiling>> GetByClientIdAsync(int clientId, CancellationToken ct = default);
+    Task<TaxFiling?> GetByIdAsync(int id, CancellationToken ct = default);
+    Task<TaxFiling?> CreateAsync(TaxFiling filing, CancellationToken ct = default);
+    Task<TaxFiling?> UpdateAsync(int id, TaxFiling filing, CancellationToken ct = default);
+    Task<bool> DeleteAsync(int id, CancellationToken ct = default);
+}
+
+public class TaxFilingBrowserClient : ITaxFilingBrowserClient
+{
+    private readonly HttpClient _http;
+    private readonly ILogger<TaxFilingBrowserClient> _logger;
+    private readonly ITokenStore _tokenStore;
+
+    public TaxFilingBrowserClient(HttpClient http, ILogger<TaxFilingBrowserClient> logger, ITokenStore tokenStore)
+    {
+        _http = http;
+        _logger = logger;
+        _tokenStore = tokenStore;
+    }
+
+    private void EnsureAuthHeader()
+    {
+        if (!string.IsNullOrEmpty(_tokenStore.AccessToken))
+            _http.DefaultRequestHeaders.Authorization = new("Bearer", _tokenStore.AccessToken);
+        else
+            _http.DefaultRequestHeaders.Authorization = null;
+    }
+
+    public async Task<IEnumerable<TaxFiling>> GetUpcomingAsync(int daysAhead = 30, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var result = await _http.GetFromJsonAsync<TaxFilingListResponse>(
+                $"taxfiling/upcoming?daysAhead={daysAhead}", cancellationToken: ct);
+            return result?.Data ?? [];
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch upcoming filings");
+            throw;
+        }
+    }
+
+    public async Task<IEnumerable<TaxFiling>> GetByClientIdAsync(int clientId, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var result = await _http.GetFromJsonAsync<TaxFilingListResponse>(
+                $"taxfiling/client/{clientId}", cancellationToken: ct);
+            return result?.Data ?? [];
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch filings for client {ClientId}", clientId);
+            throw;
+        }
+    }
+
+    public async Task<TaxFiling?> GetByIdAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            return await _http.GetFromJsonAsync<TaxFiling>(
+                $"taxfiling/{id}", cancellationToken: ct);
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to fetch filing {FilingId}", id);
+            throw;
+        }
+    }
+
+    public async Task<TaxFiling?> CreateAsync(TaxFiling filing, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.PostAsJsonAsync("taxfiling", filing, cancellationToken: ct);
+            if (!response.IsSuccessStatusCode)
+                return null;
+
+            var content = await response.Content.ReadAsStringAsync(ct);
+            return System.Text.Json.JsonSerializer.Deserialize<TaxFiling>(
+                content,
+                new System.Text.Json.JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to create filing");
+            throw;
+        }
+    }
+
+    public async Task<TaxFiling?> UpdateAsync(int id, TaxFiling filing, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.PutAsJsonAsync($"taxfiling/{id}", filing, cancellationToken: ct);
+            if (!response.IsSuccessStatusCode)
+                return null;
+
+            var content = await response.Content.ReadAsStringAsync(ct);
+            return System.Text.Json.JsonSerializer.Deserialize<TaxFiling>(
+                content,
+                new System.Text.Json.JsonSerializerOptions { PropertyNameCaseInsensitive = true });
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to update filing {FilingId}", id);
+            throw;
+        }
+    }
+
+    public async Task<bool> DeleteAsync(int id, CancellationToken ct = default)
+    {
+        try
+        {
+            EnsureAuthHeader();
+            var response = await _http.DeleteAsync($"taxfiling/{id}", cancellationToken: ct);
+            return response.IsSuccessStatusCode;
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogError(ex, "Failed to delete filing {FilingId}", id);
+            throw;
+        }
+    }
+
+    private class TaxFilingListResponse
+    {
+        public List<TaxFiling> Data { get; set; } = [];
+    }
+}

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; }
+}

TaxBaik.Web.Client/TaxBaik.Web.Client.csproj

@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk.BlazorWebAssembly">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <RootNamespace>TaxBaik.WasmClient</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\TaxBaik.Application\TaxBaik.Application.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly" Version="10.0.9" />
+    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="10.0.9" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.AspNetCore.Components.Authorization" Version="10.0.9" />
+    <PackageReference Include="Microsoft.Extensions.Http" Version="10.0.9" />
+    <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="8.19.1" />
+    <PackageReference Include="MudBlazor" Version="6.10.0" />
+    <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="8.19.1" />
+  </ItemGroup>
+
+</Project>

TaxBaik.Web.Client/_Imports.razor

@@ -0,0 +1,13 @@
+@using System.Net.Http
+@using System.Net.Http.Json
+@using Microsoft.AspNetCore.Authorization
+@using Microsoft.AspNetCore.Components.Authorization
+@using Microsoft.AspNetCore.Components.Forms
+@using Microsoft.AspNetCore.Components.Routing
+@using Microsoft.AspNetCore.Components.Web
+@using Microsoft.AspNetCore.Components.Web.Virtualization
+@using Microsoft.AspNetCore.Components.WebAssembly.Http
+@using Microsoft.JSInterop
+@using MudBlazor
+@using TaxBaik.WasmClient
+@using static Microsoft.AspNetCore.Components.Web.RenderMode