docs: add XML documentation and ConfigManager implementation plans

Add comprehensive XML documentation (param/returns tags) across 132 source
files to improve IntelliSense and API discoverability. Include ConfigManager
design documents and implementation plans for phases 1-9.

NEW/src/JdeScoping.Api/Hubs/StatusHub.cs

@@ -16,6 +16,12 @@ public class StatusHub : Hub
     private readonly ILogger<StatusHub> _logger;
     private readonly TimeProvider _timeProvider;
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="StatusHub"/> class.
+    /// </summary>
+    /// <param name="cache">The memory cache for caching status updates.</param>
+    /// <param name="logger">The logger instance.</param>
+    /// <param name="timeProvider">The time provider for getting current UTC time.</param>
     public StatusHub(IMemoryCache cache, ILogger<StatusHub> logger, TimeProvider timeProvider)
     {
         _cache = cache;