Integrate DevExpress Web Dashboard into API and Blazor

Added DevExpress Dashboard to ASP.NET Core API and both Blazor WASM/Server frontends. Configured dashboard storage, sample data source, and API endpoint. Updated Blazor projects with dashboard packages, styles, and a new dashboard page. Navigation and configuration updated to support dashboard integration.

DbFirst.BlazorWebApp/Components/Layout/NavMenu.razor

@@ -25,6 +25,11 @@
                 <span class="bi bi-list-nested-nav-menu" aria-hidden="true"></span> Weather
             </NavLink>
         </div>
+        <div class="nav-item px-3">
+            <NavLink class="nav-link" href="dashboard">
+                <span class="oi oi-list-rich" aria-hidden="true"></span> Web Dashboard
+            </NavLink>
+        </div>
     </nav>
 </div>