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.Admin/Components/Pages/Inquiries/InquiryDetail.razor

@@ -37,9 +37,9 @@
             <MudItem xs="12">
                 <MudText Typo="Typo.subtitle1">상태</MudText>
                 <MudSelect @bind-Value="inquiry.Status" Label="상태 변경">
-                    <MudSelectItem Value="new">신규</MudSelectItem>
-                    <MudSelectItem Value="contacted">연락함</MudSelectItem>
-                    <MudSelectItem Value="completed">완료</MudSelectItem>
+                    <MudSelectItem Value="@("new")">신규</MudSelectItem>
+                    <MudSelectItem Value="@("contacted")">연락함</MudSelectItem>
+                    <MudSelectItem Value="@("completed")">완료</MudSelectItem>
                 </MudSelect>
             </MudItem>
         </MudGrid>