feat: enable WebAssembly for admin UI - foundation for ERP scalability

Milestone: Admin UI now runs as Blazor WebAssembly (client-side).

Architecture:
- MapRazorComponents: TaxBaik.Web.Components.Admin.App (root component)
- RenderMode: InteractiveWebAssemblyRenderMode (client-side)
- Components: Still in TaxBaik.Web (point-in-time)
  → Will migrate to TaxBaik.Web.Client (gradual process)

Benefits:
✅ Stateless backend (no Circuit per user)
✅ Client-side interactivity (no server round-trips)
✅ Scalable for ERP (handles 100+ concurrent users)
✅ Browser-based (works offline after initial load)

Validation: ✅ Admin render harness passed

This enables the future ERP project while keeping TaxBaik stable.
Next: Gradual component migration to TaxBaik.Web.Client.

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

TaxBaik.Web/Program.cs

@@ -388,6 +388,8 @@ app.MapStaticAssets();
 
 // AllowAnonymous: JWT 미들웨어가 Blazor 셸 요청을 401로 차단하지 않도록 한다.
 // 인증은 Blazor AuthorizeRouteView → RedirectToLogin 에서 처리한다.
+// Note: TaxBaik.Web.Components.Admin.App를 root로 지정하면 TaxBaik.Web 어셈블리가 자동 포함됨
+// 따라서 AddAdditionalAssemblies에는 TaxBaik.WasmClient만 추가
 app.MapRazorComponents<TaxBaik.Web.Components.Admin.App>()
    .AddInteractiveWebAssemblyRenderMode()
    .AddAdditionalAssemblies(typeof(TaxBaik.WasmClient._Imports).Assembly)