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.Tests/Gateway/Dashboard/DashboardApiKeyAuthorizationTests.cs

@@ -5,6 +5,7 @@ namespace ZB.MOM.WW.MxGateway.Tests.Gateway.Dashboard;
 
 public sealed class DashboardApiKeyAuthorizationTests
 {
+    /// <summary>Verifies that CanManage returns true for authenticated admin user.</summary>
     [Fact]
     public void CanManage_AuthenticatedAdmin_ReturnsTrue()
     {
@@ -14,6 +15,7 @@ public sealed class DashboardApiKeyAuthorizationTests
         Assert.True(authorization.CanManage(user));
     }
 
+    /// <summary>Verifies that CanManage returns false for anonymous user.</summary>
     [Fact]
     public void CanManage_AnonymousUser_ReturnsFalse()
     {
@@ -23,6 +25,7 @@ public sealed class DashboardApiKeyAuthorizationTests
         Assert.False(authorization.CanManage(user));
     }
 
+    /// <summary>Verifies that CanManage returns false for authenticated viewer user.</summary>
     [Fact]
     public void CanManage_AuthenticatedViewer_ReturnsFalse()
     {