Initialize SignalR hub in OnAfterRenderAsync after first render

Moved SignalR hub connection setup from OnInitializedAsync to OnAfterRenderAsync, ensuring initialization occurs only after the component's first render. This prevents premature connection attempts and aligns with best practices for component lifecycle management.

DbFirst.BlazorWebApp/Components/Pages/Dashboard.razor

@@ -51,6 +51,11 @@
     protected override async Task OnInitializedAsync()
     {
         await RefreshDashboards();
+    }
+
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (!firstRender) return;
 
         _hubConnection = new HubConnectionBuilder()
             .WithUrl(HubEndpoint)