Add Clock page with live DB time and TimeApiClient service

Introduced a new Clock page that displays and updates the current database server time every second by calling a backend API. Added the TimeApiClient service to handle API requests for the server time. Registered TimeApiClient in Program.cs and updated the navigation menu to include a link to the new Clock page. Includes error handling and custom UI styling for the clock display.

DbFirst.BlazorWebApp/Services/TimeApiClient.cs

@@ -0,0 +1,27 @@
+using System.Net.Http.Json;
+
+namespace DbFirst.BlazorWebApp.Services;
+
+public class TimeApiClient
+{
+    private readonly HttpClient _httpClient;
+    private const string Endpoint = "api/time";
+
+    public TimeApiClient(HttpClient httpClient)
+    {
+        _httpClient = httpClient;
+    }
+
+    public async Task<DateTime?> InsertAndGetLastAsync()
+    {
+        var response = await _httpClient.PostAsync(Endpoint, null);
+        response.EnsureSuccessStatusCode();
+        var result = await response.Content.ReadFromJsonAsync<TimeResponse>();
+        return result?.Now;
+    }
+
+    private sealed class TimeResponse
+    {
+        public DateTime? Now { get; set; }
+    }
+}