feat: implement admin inquiry create/edit/delete functionality

Core Components:
- Create reusable InquiryForm.razor component following SOLID principles
- Implement InquiryCreate.razor for registering new inquiries (offline, phone)
- Implement InquiryEdit.razor for modifying existing inquiries with delete
- Add DeleteAsync method to InquiryRepository and InquiryService
- Update InquiryList with 'Create' button and Edit link in table

Architecture:
- InquiryForm: Encapsulates form logic, can be reused for create/edit
- Service Layer: All operations go through InquiryService for cache invalidation
- Repository Pattern: Database operations isolated in InquiryRepository
- UI Consistency: Both pages follow admin-page-hero pattern

Features:
- Admin can create inquiries from phone/offline consultations
- Admin can modify inquiry details (name, phone, email, message, status, memo)
- Admin can delete inquiries with confirmation dialog
- All operations update dashboard cache
- Status validation and error handling throughout

Testing:
- Updated FakeInquiryRepository in tests to implement DeleteAsync

TaxBaik.Web/Components/Admin/InquiryTable.razor

@@ -26,7 +26,9 @@
                 <td>@inquiry.CreatedAt.ToString("yyyy-MM-dd")</td>
                 <td>
                     <MudButton Size="Size.Small" Variant="Variant.Outlined" Color="Color.Primary"
-                        Href="@($"/taxbaik/admin/inquiries/{inquiry.Id}")">문의 내용 확인</MudButton>
+                        Href="@($"/taxbaik/admin/inquiries/{inquiry.Id}")">보기</MudButton>
+                    <MudButton Size="Size.Small" Variant="Variant.Outlined" Color="Color.Info"
+                        Href="@($"/taxbaik/admin/inquiries/{inquiry.Id}/edit")">수정</MudButton>
                 </td>
             </tr>
         }