docs+ui: backfill XML doc comments and finish dashboard layout pass

Adds missing <summary>/<param> XML docs across 99 server, worker, and test
files so CommentChecker reports zero issues (TreatWarningsAsErrors needs the
analyzer clean). Bundles in WIP dashboard work: NavSection extraction,
MainLayout/site.css/js styling alignment, and DashboardOptions/Auth tweaks.

src/ZB.MOM.WW.MxGateway.Server/Dashboard/Hubs/DashboardEventBroadcaster.cs

@@ -14,6 +14,9 @@ public sealed class DashboardEventBroadcaster(
     IHubContext<EventsHub> hubContext,
     ILogger<DashboardEventBroadcaster> logger) : IDashboardEventBroadcaster
 {
+    /// <summary>Publishes an MX event to connected dashboard clients.</summary>
+    /// <param name="sessionId">The session identifier.</param>
+    /// <param name="mxEvent">The MX event to publish.</param>
     public void Publish(string sessionId, MxEvent mxEvent)
     {
         if (string.IsNullOrEmpty(sessionId) || mxEvent is null)