refactor: complete WebAssembly migration - proper architecture

Phase 8: Complete WebAssembly 렌더 모드 전환 (정공법)

Migration Summary:
- ALL Admin components → TaxBaik.Web.Client
- Routes.razor, Pages/*, Layout/*, Shared/*, Forms/*
- App.razor → TaxBaik.WasmClient (호스트 컴포넌트)
- Shared utilities → TaxBaik.Application.Utils

Architecture:
✅ App.razor: TaxBaik.WasmClient (WebAssembly, 호스트)
✅ Routes + Pages: TaxBaik.WasmClient (WebAssembly)
✅ Layout + Shared + Forms: TaxBaik.WasmClient (WebAssembly)
✅ Services: TaxBaik.Web (API-First)

Key Changes:
- Namespaces: TaxBaik.Web.Components.Admin → TaxBaik.WasmClient.Components.Admin
- Shared utilities: TaxBaik.Application.Utils (single source of truth)
- Program.cs: MapRazorComponents<TaxBaik.WasmClient.Components.Admin.App>()
- _Imports.razor: Components/Admin 폴더에 재구성

Build Status: ✅ 0 errors, 0 warnings

Benefits:
- Stateless server (no Circuit memory)
- Client-side rendering (WebAssembly)
- Unlimited concurrent users (horizontal scaling)
- ERP-ready architecture

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

TaxBaik.Web/Components/Admin/Shared/ConfirmDialog.razor

@@ -1,20 +0,0 @@
-@using MudBlazor
-
-<MudDialog>
-    <DialogContent>
-        <MudText>@Message</MudText>
-    </DialogContent>
-    <DialogActions>
-        <MudButton OnClick="Cancel">취소</MudButton>
-        <MudButton Color="Color.Error" Variant="Variant.Filled" OnClick="Confirm">삭제</MudButton>
-    </DialogActions>
-</MudDialog>
-
-@code {
-    [CascadingParameter] MudDialogInstance MudDialog { get; set; } = null!;
-    [Parameter] public string Title { get; set; } = "";
-    [Parameter] public string Message { get; set; } = "";
-
-    private void Cancel() => MudDialog.Cancel();
-    private void Confirm() => MudDialog.Close();
-}