fix: add admin-page-hero to detail pages for loading indicator

InquiryDetail and ClientDetail pages were missing the admin-page-hero
section, causing the loading overlay to remain stuck on navigation.
The loading indicator (admin-session.js) detects page.admin-page-hero
to know when to hide the overlay.

Now all detail pages show smooth loading indicators on navigation.

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

TaxBaik.Web/Components/Admin/Pages/Clients/ClientDetail.razor

@@ -8,6 +8,14 @@
 
 <PageTitle>고객 상세</PageTitle>
 
+<section class="admin-page-hero">
+    <div>
+        <MudText Typo="Typo.caption" Class="admin-eyebrow">Client Details</MudText>
+        <MudText Typo="Typo.h4" Class="admin-page-title">고객 상세</MudText>
+        <MudText Typo="Typo.body2" Class="admin-page-subtitle">고객 정보와 상담 이력을 관리합니다.</MudText>
+    </div>
+</section>
+
 @if (client == null)
 {
     <MudText>고객을 찾을 수 없습니다.</MudText>

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

@@ -7,6 +7,14 @@
 
 <PageTitle>문의 상세</PageTitle>
 
+<section class="admin-page-hero">
+    <div>
+        <MudText Typo="Typo.caption" Class="admin-eyebrow">Inquiry Details</MudText>
+        <MudText Typo="Typo.h4" Class="admin-page-title">문의 상세</MudText>
+        <MudText Typo="Typo.body2" Class="admin-page-subtitle">문의 정보를 확인하고 처리 상태를 관리합니다.</MudText>
+    </div>
+</section>
+
 @if (inquiry != null)
 {
     <MudButton Variant="Variant.Outlined"