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.Worker.Tests/MxAccess/MxAccessEventMapperTests.cs

@@ -227,6 +227,7 @@ public sealed class MxAccessEventMapperTests
     }
 
     /// <summary>Verifies unparseable or empty timestamp input is rejected without throwing.</summary>
+    /// <param name="text">Unparseable or empty timestamp string.</param>
     [Theory]
     [InlineData(null)]
     [InlineData("")]