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.Client/Components/Admin/Pages/Blog/BlogEdit.razor

@@ -0,0 +1,154 @@
+@page "/admin/blog/{id:int}/edit"
+@attribute [Authorize]
+@using TaxBaik.Application.DTOs
+@using TaxBaik.WasmClient.Components.Admin.Pages.Blog
+@inject IBlogBrowserClient BlogClient
+@inject ICategoryBrowserClient CategoryClient
+@inject NavigationManager Navigation
+@inject ISnackbar Snackbar
+@inject IDialogService DialogService
+
+<PageTitle>포스트 수정</PageTitle>
+
+<AdminCrudPageShell Title="포스트 수정"
+                    Eyebrow="Content"
+                    Subtitle="블로그 포스트를 수정합니다."
+                    Loading="@isLoading"
+                    SkeletonContent="@EditorSkeleton"
+                    OnCancel="@GoBack">
+    @if (post == null)
+{
+    <MudAlert Severity="Severity.Error" Class="mt-4">포스트를 찾을 수 없습니다.</MudAlert>
+}
+else
+{
+    <MudPaper Class="pa-4 mt-4" Elevation="1">
+        <BlogForm Model="model" Categories="categories" SubmitText="저장" OnSubmit="SavePost" />
+        <div class="mt-4">
+            <MudButton Variant="Variant.Outlined" Color="Color.Error" @onclick="DeletePost">삭제</MudButton>
+        </div>
+    </MudPaper>
+}
+</AdminCrudPageShell>
+
+@code {
+    [Parameter]
+    public int Id { get; set; }
+
+    private TaxBaik.Application.DTOs.BlogPostResponseDto? post;
+    private IReadOnlyList<Domain.Entities.Category> categories = [];
+    private BlogForm.BlogFormModel model = new();
+    private bool isLoading = true;
+
+    private RenderFragment EditorSkeleton => builder =>
+    {
+        builder.OpenComponent<AdminSkeletonRows>(0);
+        builder.AddAttribute(1, "Rows", 5);
+        builder.AddAttribute(2, "Columns", 3);
+        builder.CloseComponent();
+    };
+
+    protected override async Task OnInitializedAsync()
+    {
+        try
+        {
+            post = await BlogClient.GetByIdAsync(Id);
+            if (post != null)
+            {
+                categories = await CategoryClient.GetAllAsync();
+                MapPostToModel(post);
+            }
+        }
+        catch (Exception ex)
+        {
+            Snackbar.Add($"포스트 로드 실패: {ex.Message}", Severity.Error);
+        }
+        finally
+        {
+            isLoading = false;
+        }
+    }
+
+    private void MapPostToModel(TaxBaik.Application.DTOs.BlogPostResponseDto post)
+    {
+        model.Title = post.Title;
+        model.Content = post.Content;
+        model.CategoryId = post.CategoryId;
+        model.Tags = post.Tags;
+        model.SeoTitle = post.SeoTitle;
+        model.SeoDescription = post.SeoDescription;
+        model.IsPublished = post.IsPublished;
+    }
+
+    private void GoBack()
+    {
+        Navigation.NavigateTo("/taxbaik/admin/blog");
+    }
+
+    private async Task SavePost()
+    {
+        if (post == null)
+            return;
+
+        try
+        {
+            var result = await BlogClient.UpdateAsync(post.Id, new CreateBlogPostDto
+            {
+                Title = model.Title,
+                Content = model.Content,
+                CategoryId = model.CategoryId,
+                Tags = model.Tags,
+                SeoTitle = model.SeoTitle,
+                SeoDescription = model.SeoDescription,
+                IsPublished = model.IsPublished
+            });
+
+            if (result == null)
+            {
+                Snackbar.Add("저장 실패: 포스트를 저장하지 못했습니다.", Severity.Error);
+                return;
+            }
+
+            Snackbar.Add("포스트가 저장되었습니다.", Severity.Success);
+            Navigation.NavigateTo("/taxbaik/admin/blog");
+        }
+        catch (ValidationException ex)
+        {
+            Snackbar.Add(ex.Message, Severity.Error);
+        }
+        catch (Exception ex)
+        {
+            Snackbar.Add($"저장 실패: {ex.Message}", Severity.Error);
+        }
+    }
+
+    private async Task DeletePost()
+    {
+        if (post == null)
+            return;
+
+        var result = await DialogService.ShowMessageBox(
+            "포스트 삭제",
+            "정말 삭제하시겠습니까? 이 작업은 취소할 수 없습니다.",
+            "삭제", "취소");
+
+        if (result != true)
+            return;
+
+        try
+        {
+            var deleted = await BlogClient.DeleteAsync(post.Id);
+            if (!deleted)
+            {
+                Snackbar.Add("삭제 실패: 포스트를 삭제하지 못했습니다.", Severity.Error);
+                return;
+            }
+            Snackbar.Add("포스트가 삭제되었습니다.", Severity.Success);
+            Navigation.NavigateTo("/taxbaik/admin/blog");
+        }
+        catch (Exception ex)
+        {
+            Snackbar.Add($"삭제 실패: {ex.Message}", Severity.Error);
+        }
+    }
+}