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/DashboardSessionAdminServiceTests.cs

@@ -9,6 +9,7 @@ namespace ZB.MOM.WW.MxGateway.Tests.Gateway.Dashboard;
 
 public sealed class DashboardSessionAdminServiceTests
 {
+    /// <summary>Verifies that a viewer cannot close a session.</summary>
     [Fact]
     public async Task CloseSessionAsync_ViewerCannotManage()
     {
@@ -24,6 +25,7 @@ public sealed class DashboardSessionAdminServiceTests
         Assert.Equal(0, sessionManager.CloseCount);
     }
 
+    /// <summary>Verifies that an admin can close a session.</summary>
     [Fact]
     public async Task CloseSessionAsync_AdminClosesSession()
     {
@@ -40,6 +42,7 @@ public sealed class DashboardSessionAdminServiceTests
         Assert.Equal("session-1", sessionManager.LastClosedSessionId);
     }
 
+    /// <summary>Verifies that closing a missing session returns a friendly error message.</summary>
     [Fact]
     public async Task CloseSessionAsync_WhenSessionMissing_ReportsFriendlyError()
     {
@@ -58,6 +61,7 @@ public sealed class DashboardSessionAdminServiceTests
         Assert.Contains("not found", result.Message, StringComparison.OrdinalIgnoreCase);
     }
 
+    /// <summary>Verifies that a viewer cannot kill a worker.</summary>
     [Fact]
     public async Task KillWorkerAsync_ViewerCannotManage()
     {
@@ -73,6 +77,7 @@ public sealed class DashboardSessionAdminServiceTests
         Assert.Equal(0, sessionManager.KillCount);
     }
 
+    /// <summary>Verifies that an admin can kill a worker.</summary>
     [Fact]
     public async Task KillWorkerAsync_AdminKillsWorker()
     {
@@ -95,6 +100,7 @@ public sealed class DashboardSessionAdminServiceTests
         Assert.Equal("dashboard-admin-kill", sessionManager.LastKillReason);
     }
 
+    /// <summary>Verifies that killing a worker with a blank session ID returns failure.</summary>
     [Fact]
     public async Task KillWorkerAsync_BlankSessionId_ReturnsFailure()
     {
@@ -130,6 +136,7 @@ public sealed class DashboardSessionAdminServiceTests
         Assert.Equal(0, sessionManager.CloseCount);
     }
 
+    /// <summary>Verifies that CanManage rejects unauthenticated users and viewers.</summary>
     [Fact]
     public void CanManage_RejectsUnauthenticatedAndViewer()
     {
@@ -209,22 +216,31 @@ public sealed class DashboardSessionAdminServiceTests
 
     private sealed class FakeSessionManager : ISessionManager
     {
+        /// <summary>Gets the number of times CloseSessionAsync was invoked.</summary>
         public int CloseCount { get; private set; }
 
+        /// <summary>Gets the number of times KillWorkerAsync was invoked.</summary>
         public int KillCount { get; private set; }
 
+        /// <summary>Gets the last session ID passed to CloseSessionAsync.</summary>
         public string? LastClosedSessionId { get; private set; }
 
+        /// <summary>Gets the last session ID passed to KillWorkerAsync.</summary>
         public string? LastKilledSessionId { get; private set; }
 
+        /// <summary>Gets the last reason string passed to KillWorkerAsync.</summary>
         public string? LastKillReason { get; private set; }
 
+        /// <summary>Gets a value indicating whether CloseSessionAsync should throw SessionNotFound.</summary>
         public bool CloseThrowsNotFound { get; init; }
 
+        /// <summary>Gets the exception CloseSessionAsync should throw unexpectedly.</summary>
         public Exception? CloseThrowsUnexpected { get; init; }
 
+        /// <summary>Gets the exception KillWorkerAsync should throw unexpectedly.</summary>
         public Exception? KillThrowsUnexpected { get; init; }
 
+        /// <inheritdoc />
         public Task<GatewaySession> OpenSessionAsync(
             SessionOpenRequest request,
             string? clientIdentity,
@@ -233,6 +249,7 @@ public sealed class DashboardSessionAdminServiceTests
             throw new NotSupportedException();
         }
 
+        /// <inheritdoc />
         public bool TryGetSession(
             string sessionId,
             [MaybeNullWhen(false)] out GatewaySession session)
@@ -241,6 +258,7 @@ public sealed class DashboardSessionAdminServiceTests
             return false;
         }
 
+        /// <inheritdoc />
         public Task<WorkerCommandReply> InvokeAsync(
             string sessionId,
             WorkerCommand command,
@@ -249,6 +267,7 @@ public sealed class DashboardSessionAdminServiceTests
             throw new NotSupportedException();
         }
 
+        /// <inheritdoc />
         public IAsyncEnumerable<WorkerEvent> ReadEventsAsync(
             string sessionId,
             CancellationToken cancellationToken)
@@ -256,6 +275,7 @@ public sealed class DashboardSessionAdminServiceTests
             throw new NotSupportedException();
         }
 
+        /// <inheritdoc />
         public Task<SessionCloseResult> CloseSessionAsync(
             string sessionId,
             CancellationToken cancellationToken)
@@ -277,6 +297,7 @@ public sealed class DashboardSessionAdminServiceTests
             return Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
         }
 
+        /// <inheritdoc />
         public Task<SessionCloseResult> KillWorkerAsync(
             string sessionId,
             string reason,
@@ -293,6 +314,7 @@ public sealed class DashboardSessionAdminServiceTests
             return Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
         }
 
+        /// <inheritdoc />
         public Task<int> CloseExpiredLeasesAsync(
             DateTimeOffset now,
             CancellationToken cancellationToken)
@@ -300,6 +322,7 @@ public sealed class DashboardSessionAdminServiceTests
             return Task.FromResult(0);
         }
 
+        /// <inheritdoc />
         public Task ShutdownAsync(CancellationToken cancellationToken)
         {
             return Task.CompletedTask;