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/Components/Admin/Shared/CommonCodeSelect.razor

@@ -1,56 +0,0 @@
-@using TaxBaik.Domain.Entities
-@using TaxBaik.Web.Services.AdminClients
-@inject ICommonCodeBrowserClient CommonCodeClient
-
-<MudSelect T="string"
-           Value="Value"
-           ValueChanged="ValueChanged"
-           Label="@Label"
-           Variant="@Variant"
-           FullWidth="@FullWidth"
-           Class="@Class"
-           Required="@Required"
-           Clearable="@Clearable"
-           Disabled="@Disabled">
-    @if (!string.IsNullOrWhiteSpace(Placeholder))
-    {
-        <MudSelectItem Value="@string.Empty">@Placeholder</MudSelectItem>
-    }
-    @foreach (var item in items)
-    {
-        <MudSelectItem Value="@item.CodeValue">@item.CodeName</MudSelectItem>
-    }
-</MudSelect>
-
-@code {
-    [Parameter] public string? Value { get; set; }
-    [Parameter] public EventCallback<string?> ValueChanged { get; set; }
-    [Parameter] public string Group { get; set; } = string.Empty;
-    [Parameter] public string Label { get; set; } = string.Empty;
-    [Parameter] public Variant Variant { get; set; } = Variant.Outlined;
-    [Parameter] public bool FullWidth { get; set; } = true;
-    [Parameter] public string? Class { get; set; }
-    [Parameter] public bool Required { get; set; }
-    [Parameter] public bool Clearable { get; set; }
-    [Parameter] public bool Disabled { get; set; }
-    [Parameter] public string? Placeholder { get; set; }
-
-    private List<CommonCode> items = [];
-
-    protected override async Task OnParametersSetAsync()
-    {
-        var normalizedGroup = Group?.Trim() ?? string.Empty;
-        if (!string.Equals(normalizedGroup, _loadedGroup, StringComparison.OrdinalIgnoreCase))
-        {
-            _loadedGroup = normalizedGroup;
-            items = string.IsNullOrWhiteSpace(normalizedGroup)
-                ? []
-                : (await CommonCodeClient.GetByGroupAsync(normalizedGroup))
-                    .OrderBy(x => x.SortOrder)
-                    .ThenBy(x => x.CodeName)
-                    .ToList();
-        }
-    }
-
-    private string? _loadedGroup;
-}