fix: resolve Inquiry data rendering issue on page load

- Move MudTabs inside MudPaper always visible structure
- Only render MudTabs content (with data) after isLoading becomes false
- Add null/empty check in InquiryTable.OnParametersSet()
- Add error handling in InquiryList data loading

Previously, MudTabs would render before data loaded, causing child
InquiryTable components to mount with empty Inquiries list. After
data loaded, child components weren't re-rendered because Blazor
didn't detect parameter changes in that scenario.

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

TaxBaik.Web/Components/Admin/InquiryTable.razor

@@ -44,6 +44,12 @@
 
     protected override void OnParametersSet()
     {
+        if (Inquiries == null || Inquiries.Count == 0)
+        {
+            filteredInquiries = [];
+            return;
+        }
+
         filteredInquiries = string.IsNullOrEmpty(Status)
             ? Inquiries
             : Inquiries.Where(x => x.Status == Status).ToList();

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

@@ -13,13 +13,13 @@
     </div>
 </section>
 
+<MudPaper Class="admin-surface" Elevation="0">
 @if (isLoading)
 {
     <MudProgressCircular Indeterminate="true" Class="ma-4" />
 }
 else
 {
-    <MudPaper Class="admin-surface" Elevation="0">
     <MudTabs Rounded="true" Elevation="0" Class="admin-tabs">
         <MudTabPanel Text="전체">
             <InquiryTable Inquiries="allInquiries" Status="" />
@@ -40,8 +40,8 @@ else
             <InquiryTable Inquiries="allInquiries" Status="closed" />
         </MudTabPanel>
     </MudTabs>
-    </MudPaper>
 }
+</MudPaper>
 
 @code {
     private bool isLoading = true;
@@ -49,8 +49,18 @@ else
 
     protected override async Task OnInitializedAsync()
     {
-        var (items, _) = await InquiryClient.GetPagedAsync(1, 200);
-        allInquiries = items.ToList();
-        isLoading = false;
+        try
+        {
+            var (items, _) = await InquiryClient.GetPagedAsync(1, 200);
+            allInquiries = items.ToList();
+        }
+        catch
+        {
+            allInquiries = [];
+        }
+        finally
+        {
+            isLoading = false;
+        }
     }
 }