Huge updates

timetracker.Client/Services/ClientAuthService.cs

@@ -71,4 +71,14 @@ public class ClientAuthService : IAuthService
         }
         return null;
     }
+
+    public async Task<string?> ChangePasswordAsync(int userId, string currentPassword, string newPassword)
+    {
+        var response = await _http.PutAsJsonAsync($"api/users/{userId}/change-password", new { CurrentPassword = currentPassword, NewPassword = newPassword });
+        if (!response.IsSuccessStatusCode)
+        {
+            return await response.Content.ReadAsStringAsync();
+        }
+        return null;
+    }
 }