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/appsettings.json

@@ -5,5 +5,6 @@
       "Microsoft.AspNetCore": "Warning"
     }
   },
+  "ApiBaseUrl": "https://localhost:7204/",
   "AllowedHosts": "*"
 }