fix(setup): cancel wizard session before disconnect to prevent stale-session retry errors

When wizard.next timed out (e.g. Teams channel selection hanging),
EnterWizardErrorAsync called DisconnectAsync which nulled _client, then
showed "Start wizard again" / "Skip wizard" buttons. CancelCurrentSessionAsync
checked _client != null and skipped the wizard.cancel call — leaving the
server-side session active. Subsequent "Start wizard again" clicks then hit a
gateway "wizard already running" error.

Fix: replace await DisconnectAsync() with await CancelCurrentSessionAsync()
in both EnterWizardErrorAsync and StartWizardAsync. CancelCurrentSessionAsync
sends wizard.cancel (best-effort, catch ignored) then calls DisconnectAsync,
so the disconnect still happens. The session cancel is a no-op when _client
is already null or _sessionId is empty, so the first-start path is unaffected.

Closes #709

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: github-actions[bot]

src/OpenClaw.SetupEngine.UI/Pages/WizardPage.xaml.cs

@@ -56,7 +56,10 @@ private async Task StartWizardAsync()
         {
             _errorState = false;
             HideRecoveryActions();
-            await DisconnectAsync();
+            // Cancel any in-progress server-side wizard session before starting a
+            // fresh one, so the gateway doesn't reject wizard.start with "wizard
+            // already running" when recovering from a previous error.
+            await CancelCurrentSessionAsync();
             ClearConsoleBanner();
             _sessionId = "";
             _wizardStepCount = 0;
@@ -757,7 +760,10 @@ private async Task EnterWizardErrorAsync(string detail)
             return;
 
         _errorState = true;
-        await DisconnectAsync();
+        // Cancel the server-side wizard session before disconnecting so that
+        // subsequent retries (Start wizard again / Skip wizard) don't hit a
+        // "wizard already running" error from a lingering gateway session.
+        await CancelCurrentSessionAsync();
         ShowError(detail);
     }