Initial project setup: solution + 5 projects

- Domain, Infrastructure, Application (class libraries)
- Web (ASP.NET Core empty)
- Admin (Blazor Server)
- All net8.0 target framework
- Project references configured

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

TaxBaik.Admin/Pages/Counter.razor

@@ -0,0 +1,18 @@
+@page "/counter"
+
+<PageTitle>Counter</PageTitle>
+
+<h1>Counter</h1>
+
+<p role="status">Current count: @currentCount</p>
+
+<button class="btn btn-primary" @onclick="IncrementCount">Click me</button>
+
+@code {
+    private int currentCount = 0;
+
+    private void IncrementCount()
+    {
+        currentCount++;
+    }
+}