Add BlazorWebApp project and Bootstrap source map

Added new Blazor Server project `DbFirst.BlazorWebApp` with core UI components, pages, and static assets. Updated solution file to include the project. Also added `bootstrap.min.css.map` to support CSS debugging in browser developer tools.

DbFirst.BlazorWebApp/Components/Pages/Counter.razor

@@ -0,0 +1,19 @@
+@page "/counter"
+@rendermode InteractiveServer
+
+<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++;
+    }
+}