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/Alarms/GatewayAlarmMonitor.cs

@@ -683,8 +683,11 @@ public sealed class GatewayAlarmMonitor : BackgroundService, IGatewayAlarmServic
 
     private sealed class Subscriber(Channel<AlarmFeedMessage> channel, string prefix)
     {
+        /// <summary>Gets the channel for publishing alarm messages to this subscriber.</summary>
         public Channel<AlarmFeedMessage> Channel { get; } = channel;
 
+        /// <summary>Determines whether the alarm reference matches this subscriber's filter.</summary>
+        /// <param name="reference">The alarm reference to match.</param>
         public bool Matches(string reference)
         {
             return prefix.Length == 0 || reference.StartsWith(prefix, StringComparison.Ordinal);