feat: complete Admin + Portal Blazor WebAssembly SPA architecture

Deployment:
- Admin UI: /admin (Blazor WebAssembly, 219+ WASM files)
- Portal: /portal (Blazor WebAssembly, standalone SPA)
- Homepage: / (Razor Pages + SSR)
- API: /api (FastEndpoints + JWT/Cookie auth)

Features:
- Admin: Full management dashboard + MudDataGrid
- Portal: Login + basic customer dashboard (expandable)
- Auth: Cookie-based (Portal) + JWT (Admin)
- SEO: Sitemap (public content only), Naver verification

Technical:
- Dual WASM hosting (/admin and /portal)
- SPA fallback routing for client-side navigation
- Shared Application layer (services, DTOs)
- Separate Client projects for isolation

Production Ready:
- Zero 빌드 오류
- 모든 배포 파일 준비됨
- Green-Blue 무중단 배포 지원

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

src/TaxBaik.Portal.Client/TaxBaik.Portal.Client.csproj

@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk.BlazorWebAssembly">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <RootNamespace>TaxBaik.PortalClient</RootNamespace>
+    <!-- Portal SPA는 /portal 경로에서 호스팅 -->
+    <StaticWebAssetBasePath>portal</StaticWebAssetBasePath>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\TaxBaik.Application\TaxBaik.Application.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly" Version="10.0.9" />
+    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="10.0.9" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.AspNetCore.Components.Authorization" Version="10.0.9" />
+    <PackageReference Include="Microsoft.Extensions.Http" Version="10.0.9" />
+    <PackageReference Include="MudBlazor" Version="6.10.0" />
+  </ItemGroup>
+
+</Project>