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.Application/Services/InquiryService.cs

@@ -89,6 +89,12 @@ public class InquiryService(
         memoryCache.Remove(AdminDashboardService.CacheKey);
     }
 
+    public async Task DeleteAsync(int id, CancellationToken ct = default)
+    {
+        await repository.DeleteAsync(id, ct);
+        memoryCache.Remove(AdminDashboardService.CacheKey);
+    }
+
     private static int NormalizePage(int page) => Math.Max(1, page);
 
     private static int NormalizePageSize(int pageSize) => Math.Clamp(pageSize, 1, 100);