refactor: fully integrate Browser Client into main Web server

BREAKING CHANGE: Removed TaxBaik.Web.Client project (separate WASM app)

Changes:
- Migrated all Blazor components to TaxBaik.Web/Components/Admin
- Migrated all Browser Client services to Components/Admin/Services
- Updated Program.cs to use integrated components (same assembly)
- Removed AddAdditionalAssemblies (no longer needed)
- Updated _Imports.razor with correct namespaces

Architecture:
✅ API-First: REST endpoints in TaxBaik.Web (ASP.NET Core)
✅ Client-Side: Blazor WASM components in TaxBaik.Web/Components
✅ Unified: Both API and UI served from single web server
✅ No separation: No separate client project

Result:
- Single deploy unit (TaxBaik.Web)
- API served only from web server
- Blazor renders client-side (prerender: false for protected pages)
- Monolithic web app architecture

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

src/TaxBaik.Web.Client/Services/ILocalStorageService.cs

@@ -1,8 +0,0 @@
-namespace TaxBaik.Web.Services;
-
-public interface ILocalStorageService
-{
-    Task<string?> GetItemAsStringAsync(string key);
-    Task SetItemAsStringAsync(string key, string value);
-    Task RemoveItemAsync(string key);
-}