refactor: unify inquiry status strings using constants (P1-06)

Problem: Inquiry status values were hardcoded as strings in multiple places:
- InquiryList.razor: Status="new", Status="consulting", etc.
- InquiryDetail.razor: inquiry.Status = "consulting"
- Makes it error-prone to update status values globally

Solution:
- Add public const fields to InquiryStatusMapper for all status values
- Replace hardcoded strings with constants (StatusNew, StatusConsulting, etc.)
- InquiryList and InquiryDetail now use mapper constants

Result: Single source of truth for status values. Changing a status value now
requires only updating InquiryStatusMapper, and all usages automatically update.

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

src/TaxBaik.Application/Services/InquiryStatusMapper.cs

@@ -4,6 +4,13 @@ using TaxBaik.Domain.Enums;
 
 public static class InquiryStatusMapper
 {
+    // Status storage values (database)
+    public const string StatusNew = "new";
+    public const string StatusConsulting = "consulting";
+    public const string StatusContracted = "contracted";
+    public const string StatusRejected = "rejected";
+    public const string StatusClosed = "closed";
+
     public static readonly Dictionary<string, string> Labels = new()
     {
         ["new"]        = "신규",

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

@@ -1,6 +1,7 @@
 @page "/admin/inquiries/{InquiryId:int}"
 @rendermode @(new InteractiveWebAssemblyRenderMode(prerender: false))
 @attribute [Authorize]
+@using TaxBaik.Application.Services
 @using TaxBaik.Web.Services
 @inject IInquiryBrowserClient InquiryClient
 @inject NavigationManager Navigation
@@ -179,7 +180,7 @@ else
             if (clientId > 0)
             {
                 inquiry.ClientId = clientId;
-                inquiry.Status = "consulting";
+                inquiry.Status = InquiryStatusMapper.StatusConsulting;
                 Snackbar.Add("고객 카드가 생성되었습니다.", Severity.Success);
             }
             else

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

@@ -1,6 +1,7 @@
 @page "/admin/inquiries"
 @rendermode @(new InteractiveWebAssemblyRenderMode(prerender: false))
 @attribute [Authorize]
+@using TaxBaik.Application.Services
 @using TaxBaik.Web.Services
 @inject IInquiryBrowserClient InquiryClient
 
@@ -19,19 +20,19 @@
             <InquiryTable Inquiries="allInquiries" Status="" />
         </MudTabPanel>
         <MudTabPanel Text="신규">
-            <InquiryTable Inquiries="allInquiries" Status="new" />
+            <InquiryTable Inquiries="allInquiries" Status="@InquiryStatusMapper.StatusNew" />
         </MudTabPanel>
         <MudTabPanel Text="상담중">
-            <InquiryTable Inquiries="allInquiries" Status="consulting" />
+            <InquiryTable Inquiries="allInquiries" Status="@InquiryStatusMapper.StatusConsulting" />
         </MudTabPanel>
         <MudTabPanel Text="계약완료">
-            <InquiryTable Inquiries="allInquiries" Status="contracted" />
+            <InquiryTable Inquiries="allInquiries" Status="@InquiryStatusMapper.StatusContracted" />
         </MudTabPanel>
         <MudTabPanel Text="거절">
-            <InquiryTable Inquiries="allInquiries" Status="rejected" />
+            <InquiryTable Inquiries="allInquiries" Status="@InquiryStatusMapper.StatusRejected" />
         </MudTabPanel>
         <MudTabPanel Text="종결">
-            <InquiryTable Inquiries="allInquiries" Status="closed" />
+            <InquiryTable Inquiries="allInquiries" Status="@InquiryStatusMapper.StatusClosed" />
         </MudTabPanel>
     </MudTabs>
 </AdminDataPanel>