refactor(client): replace hardcoded API URLs with ApiRoutes constants

Centralizes all API endpoint strings in ApiRoutes for consistency and
easier maintenance. Adds Hubs class for SignalR endpoints. Removes
completed plan files.

NEW/src/JdeScoping.Client/Services/RefreshStatusService.cs

@@ -1,4 +1,5 @@
 using System.Net.Http.Json;
+using JdeScoping.Core.ApiContracts;
 using JdeScoping.Core.Models.Infrastructure;
 
 namespace JdeScoping.Client.Services;
@@ -30,10 +31,8 @@ public class RefreshStatusService : IRefreshStatusService
     {
         try
         {
-            var minDtStr = minDt.ToString("yyyy-MM-dd");
-            var maxDtStr = maxDt.ToString("yyyy-MM-dd");
             var result = await _httpClient.GetFromJsonAsync<List<DataUpdateDto>>(
-                $"api/refresh-status?minDT={minDtStr}&maxDT={maxDtStr}");
+                ApiRoutes.RefreshStatus.Get(minDt, maxDt));
             return result ?? [];
         }
         catch (Exception ex)