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/Announcements/AnnouncementEdit.razor

@@ -0,0 +1,176 @@
+@page "/admin/announcements/create"
+@page "/admin/announcements/{Id:int}/edit"
+@attribute [Authorize]
+@using TaxBaik.Application.DTOs
+@using TaxBaik.Web.Services
+@using TaxBaik.WasmClient.Components.Admin.Shared
+@inject IAnnouncementBrowserClient AnnouncementClient
+@inject NavigationManager Navigation
+@inject ISnackbar Snackbar
+
+<PageTitle>@(Id.HasValue ? "공지 수정" : "공지 등록")</PageTitle>
+
+<section class="admin-page-hero">
+    <div>
+        <MudText Typo="Typo.caption" Class="admin-eyebrow">Homepage</MudText>
+        <MudText Typo="Typo.h4" Class="admin-page-title">@(Id.HasValue ? "공지 수정" : "공지 등록")</MudText>
+    </div>
+</section>
+
+<MudPaper Class="admin-surface" Elevation="0">
+    <MudForm @ref="form">
+        <MudGrid>
+            <MudItem xs="12">
+                <MudTextField @bind-Value="model.Title"
+                              Label="제목"
+                              Variant="Variant.Outlined"
+                              Required="true"
+                              RequiredError="제목을 입력하세요."
+                              HelperText="홈페이지 상단 공지 바에 표시되는 텍스트입니다." />
+            </MudItem>
+
+            <MudItem xs="12">
+                <MudTextField @bind-Value="model.Content"
+                              Label="상세 내용 (선택)"
+                              Variant="Variant.Outlined"
+                              Lines="3"
+                              HelperText="부가 설명이 있을 경우 입력합니다. 없으면 제목만 표시됩니다." />
+            </MudItem>
+
+            <MudItem xs="12" sm="6">
+                <CommonCodeSelect @bind-Value="model.DisplayType"
+                                  Group="ANNOUNCEMENT_DISPLAY_TYPE"
+                                  Label="유형"
+                                  Class="mb-0" />
+            </MudItem>
+
+            <MudItem xs="12" sm="6">
+                <MudNumericField @bind-Value="model.SortOrder"
+                                 Label="노출 순서"
+                                 Variant="Variant.Outlined"
+                                 HelperText="숫자가 클수록 먼저 표시됩니다." />
+            </MudItem>
+
+            <MudItem xs="12" sm="6">
+                <MudDatePicker @bind-Date="startsAtDate"
+                               Label="게시 시작일 (비우면 즉시)"
+                               Variant="Variant.Outlined"
+                               DateFormat="yyyy-MM-dd"
+                               Clearable="true" />
+            </MudItem>
+
+            <MudItem xs="12" sm="6">
+                <MudDatePicker @bind-Date="endsAtDate"
+                               Label="게시 종료일 (비우면 무기한)"
+                               Variant="Variant.Outlined"
+                               DateFormat="yyyy-MM-dd"
+                               Clearable="true" />
+            </MudItem>
+
+            <MudItem xs="12">
+                <MudSwitch @bind-Checked="model.IsActive"
+                           Label="@(model.IsActive ? "활성화 (홈페이지에 노출)" : "비활성화 (홈페이지 미노출)")"
+                           Color="Color.Primary" />
+            </MudItem>
+        </MudGrid>
+
+        <div class="d-flex gap-2 mt-4">
+            <MudButton Variant="Variant.Filled" Color="Color.Primary"
+                       StartIcon="@Icons.Material.Filled.Save"
+                       Disabled="isSaving"
+                       @onclick="SaveAsync">
+                @(isSaving ? "저장 중..." : "저장")
+            </MudButton>
+            <MudButton Variant="Variant.Outlined"
+                       @onclick="@(() => Navigation.NavigateTo("/taxbaik/admin/announcements"))">
+                취소
+            </MudButton>
+        </div>
+    </MudForm>
+</MudPaper>
+
+@code {
+    [Parameter] public int? Id { get; set; }
+
+    private MudForm? form;
+    private bool isSaving;
+    private DateTime? startsAtDate;
+    private DateTime? endsAtDate;
+
+    private AnnouncementDto model = new();
+
+    protected override async Task OnInitializedAsync()
+    {
+        if (Id.HasValue)
+        {
+            try
+            {
+                var entity = await AnnouncementClient.GetByIdAsync(Id.Value);
+                if (entity is null)
+                {
+                    Navigation.NavigateTo("/taxbaik/admin/announcements");
+                    return;
+                }
+                model = new AnnouncementDto
+                {
+                    Id          = entity.Id,
+                    Title       = entity.Title,
+                    Content     = entity.Content,
+                    DisplayType = entity.DisplayType,
+                    IsActive    = entity.IsActive,
+                    SortOrder   = entity.SortOrder
+                };
+                startsAtDate = entity.StartsAt?.ToLocalTime();
+                endsAtDate   = entity.EndsAt?.ToLocalTime();
+            }
+            catch
+            {
+                Navigation.NavigateTo("/taxbaik/admin/announcements");
+            }
+        }
+    }
+
+    private async Task SaveAsync()
+    {
+        if (form is null) return;
+        await form.Validate();
+        if (!form.IsValid) return;
+
+        isSaving = true;
+        try
+        {
+            model.StartsAt = startsAtDate.HasValue
+                ? DateTime.SpecifyKind(startsAtDate.Value.Date, DateTimeKind.Local).ToUniversalTime()
+                : null;
+            model.EndsAt = endsAtDate.HasValue
+                ? DateTime.SpecifyKind(endsAtDate.Value.Date.AddDays(1).AddSeconds(-1), DateTimeKind.Local).ToUniversalTime()
+                : null;
+
+            if (Id.HasValue)
+            {
+                var result = await AnnouncementClient.UpdateAsync(Id.Value, model);
+                if (result != null)
+                    Snackbar.Add("공지사항이 저장되었습니다.", Severity.Success);
+                else
+                    Snackbar.Add("저장 실패", Severity.Error);
+            }
+            else
+            {
+                var result = await AnnouncementClient.CreateAsync(model);
+                if (result != null)
+                    Snackbar.Add("공지사항이 저장되었습니다.", Severity.Success);
+                else
+                    Snackbar.Add("저장 실패", Severity.Error);
+            }
+            Navigation.NavigateTo("/taxbaik/admin/announcements");
+        }
+        catch (Exception ex)
+        {
+            Snackbar.Add($"저장 실패: {ex.Message}", Severity.Error);
+        }
+        finally
+        {
+            isSaving = false;
+        }
+    }
+}

TaxBaik.Web.Client/Components/Admin/Pages/Announcements/AnnouncementList.razor

@@ -0,0 +1,204 @@
+@page "/admin/announcements"
+@attribute [Authorize]
+@using TaxBaik.Web.Services
+@using TaxBaik.Domain.Entities
+@inject IAnnouncementBrowserClient AnnouncementClient
+@inject NavigationManager Navigation
+@inject IDialogService DialogService
+@inject ISnackbar Snackbar
+
+<PageTitle>공지사항 관리</PageTitle>
+
+<section class="admin-page-hero">
+    <div>
+        <MudText Typo="Typo.caption" Class="admin-eyebrow">Homepage</MudText>
+        <MudText Typo="Typo.h4" Class="admin-page-title">공지사항 관리</MudText>
+        <MudText Typo="Typo.body2" Class="admin-page-subtitle">홈페이지 상단에 노출되는 공지사항을 등록하고 관리합니다.</MudText>
+    </div>
+    <MudButton Variant="Variant.Filled" Color="Color.Primary"
+               StartIcon="@Icons.Material.Filled.Add"
+               Href="/taxbaik/admin/announcements/create">
+        공지 등록
+    </MudButton>
+</section>
+
+<div class="d-flex pa-4 gap-4 align-center">
+    <MudTextField @bind-Value="searchQuery" Placeholder="공지사항 제목 검색..." Adornment="Adornment.Start" 
+                  AdornmentIcon="@Icons.Material.Filled.Search" IconSize="Size.Medium" Class="flex-grow-1" Immediate="true" Clearable="true" />
+</div>
+
+<AdminDataPanel Loading="@(announcements is null)" SkeletonContent="@AnnouncementSkeleton">
+    @if (announcements is null)
+    {
+    }
+    else if (!FilteredAnnouncements.Any())
+    {
+        <div class="pa-6 text-center">
+            <MudIcon Icon="@Icons.Material.Filled.Campaign" Style="font-size:3rem; opacity:.3;" />
+            <MudText Class="mt-2 text-muted">검색 조건에 맞는 공지사항이 없습니다.</MudText>
+        </div>
+    }
+    else
+    {
+        <MudSimpleTable Striped="true" Dense="true" Class="admin-table">
+            <thead>
+                <tr>
+                    <th>제목</th>
+                    <th>유형</th>
+                    <th>상태</th>
+                    <th>게시 기간</th>
+                    <th>순서</th>
+                    <th></th>
+                </tr>
+            </thead>
+            <tbody>
+                @foreach (var item in FilteredAnnouncements)
+                {
+                    <tr>
+                        <td>@item.Title</td>
+                        <td>
+                            <MudChip Size="Size.Small" Color="@GetTypeColor(item.DisplayType)">
+                                @GetTypeLabel(item.DisplayType)
+                            </MudChip>
+                        </td>
+                        <td>
+                            @if (IsCurrentlyActive(item))
+                            {
+                                <MudChip Size="Size.Small" Color="Color.Success">노출 중</MudChip>
+                            }
+                            else if (!item.IsActive)
+                            {
+                                <MudChip Size="Size.Small" Color="Color.Default">비활성</MudChip>
+                            }
+                            else
+                            {
+                                <MudChip Size="Size.Small" Color="Color.Warning">기간 외</MudChip>
+                            }
+                        </td>
+                        <td class="small">
+                            @FormatPeriod(item)
+                        </td>
+                        <td>@item.SortOrder</td>
+                        <td>
+                            <MudButtonGroup Size="Size.Small" Variant="Variant.Outlined">
+                                <MudButton @onclick="@(() => Navigation.NavigateTo($"/taxbaik/admin/announcements/{item.Id}/edit"))">
+                                    수정
+                                </MudButton>
+                                <MudButton Color="Color.Error" @onclick="@(() => DeleteAsync(item))">
+                                    삭제
+                                </MudButton>
+                            </MudButtonGroup>
+                        </td>
+                    </tr>
+                }
+            </tbody>
+        </MudSimpleTable>
+        <MudText Typo="Typo.caption" Class="pa-2 text-muted">
+            검색 결과 @(FilteredAnnouncements.Count())개 · 총 @(announcements.Count)개
+        </MudText>
+    }
+</AdminDataPanel>
+
+@code {
+    [CascadingParameter]
+    private Task<AuthenticationState>? AuthStateTask { get; set; }
+
+    private List<Announcement>? announcements;
+    private string searchQuery = "";
+
+    private RenderFragment AnnouncementSkeleton => builder =>
+    {
+        builder.OpenComponent<AdminSkeletonRows>(0);
+        builder.AddAttribute(1, "Rows", 5);
+        builder.AddAttribute(2, "Columns", 4);
+        builder.CloseComponent();
+    };
+
+    private IEnumerable<Announcement> FilteredAnnouncements => announcements?
+        .Where(a => string.IsNullOrEmpty(searchQuery) || 
+                    a.Title.Contains(searchQuery, StringComparison.OrdinalIgnoreCase))
+        .OrderBy(a => a.SortOrder) ?? Enumerable.Empty<Announcement>();
+
+    protected override async Task OnInitializedAsync()
+    {
+        if (AuthStateTask != null)
+        {
+            var authState = await AuthStateTask;
+            if (authState.User.Identity?.IsAuthenticated == true)
+            {
+                await LoadAsync();
+            }
+        }
+    }
+
+    private async Task LoadAsync()
+    {
+        try
+        {
+            announcements = (await AnnouncementClient.GetAllAsync()).ToList();
+        }
+        catch (Exception ex)
+        {
+            Snackbar.Add($"오류: {ex.Message}", Severity.Error);
+            announcements = [];
+        }
+    }
+
+    private async Task DeleteAsync(Announcement item)
+    {
+        var confirmed = await DialogService.ShowMessageBox(
+            "공지 삭제",
+            $"'{item.Title}' 공지를 삭제하시겠습니까?",
+            yesText: "삭제", cancelText: "취소");
+
+        if (confirmed != true) return;
+
+        try
+        {
+            var success = await AnnouncementClient.DeleteAsync(item.Id);
+            if (success)
+            {
+                Snackbar.Add("공지사항이 삭제되었습니다.", Severity.Success);
+                await LoadAsync();
+            }
+            else
+            {
+                Snackbar.Add("삭제 실패", Severity.Error);
+            }
+        }
+        catch (Exception ex)
+        {
+            Snackbar.Add($"오류: {ex.Message}", Severity.Error);
+        }
+    }
+
+    private static bool IsCurrentlyActive(Announcement a)
+    {
+        if (!a.IsActive) return false;
+        var now = DateTime.UtcNow;
+        if (a.StartsAt.HasValue && a.StartsAt > now) return false;
+        if (a.EndsAt.HasValue   && a.EndsAt   < now) return false;
+        return true;
+    }
+
+    private static string FormatPeriod(Announcement a)
+    {
+        var start = a.StartsAt?.ToLocalTime().ToString("MM/dd") ?? "즉시";
+        var end   = a.EndsAt?.ToLocalTime().ToString("MM/dd")   ?? "무기한";
+        return $"{start} ~ {end}";
+    }
+
+    private static Color GetTypeColor(string type) => type switch
+    {
+        "urgent" => Color.Error,
+        "banner" => Color.Warning,
+        _        => Color.Info
+    };
+
+    private static string GetTypeLabel(string type) => type switch
+    {
+        "urgent" => "긴급",
+        "banner" => "배너",
+        _        => "일반"
+    };
+}