수정: 빌드 오류 해결 (PageModel 네임스페이스, Blazor 문법, 응답 압축)

- @model 선언에 정확한 네임스페이스 지정
- Snackbar 호출 수정 (MudBlazor 6.x 호환)
- GzipCompressionProvider import 추가
- Dashboard Color.TextSecondary 제거
- Admin App.razor MUI CSS 제거

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

TaxBaik.Web/Program.cs

@@ -1,3 +1,4 @@
+using System.IO.Compression;
 using TaxBaik.Application;
 using TaxBaik.Infrastructure;
 
@@ -7,6 +8,7 @@ builder.Services.AddRazorPages();
 builder.Services.AddMemoryCache();
 builder.Services.AddResponseCompression(opts => {
     opts.Providers.Add<GzipCompressionProvider>();
+    opts.MimeTypes = ResponseCompressionDefaults.MimeTypes.Concat(["application/atom+xml"]);
 });
 builder.Services.AddInfrastructure();
 builder.Services.AddApplication();