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/Configuration/GatewayOptions.cs

@@ -9,6 +9,7 @@ public sealed class GatewayOptions
     /// </summary>
     public AuthenticationOptions Authentication { get; init; } = new();
 
+    /// <summary>Gets LDAP configuration options.</summary>
     public LdapOptions Ldap { get; init; } = new();
 
     /// <summary>