refactor: fully integrate Browser Client into main Web server

BREAKING CHANGE: Removed TaxBaik.Web.Client project (separate WASM app)

Changes:
- Migrated all Blazor components to TaxBaik.Web/Components/Admin
- Migrated all Browser Client services to Components/Admin/Services
- Updated Program.cs to use integrated components (same assembly)
- Removed AddAdditionalAssemblies (no longer needed)
- Updated _Imports.razor with correct namespaces

Architecture:
✅ API-First: REST endpoints in TaxBaik.Web (ASP.NET Core)
✅ Client-Side: Blazor WASM components in TaxBaik.Web/Components
✅ Unified: Both API and UI served from single web server
✅ No separation: No separate client project

Result:
- Single deploy unit (TaxBaik.Web)
- API served only from web server
- Blazor renders client-side (prerender: false for protected pages)
- Monolithic web app architecture

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/TaxBaik.Web/Components/Admin/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; } = [];
+    }
+}