kate: fix crash in onSessionKilled

QTextDocument::setHtml was called while the document was still
tearing down from clear(). Defer refreshSessions to the next
event loop iteration with QTimer::singleShot(0, ...).

kate/ollie_kate.cpp

@@ -28,6 +28,7 @@
 #include <QFileInfo>
 #include <QInputDialog>
 #include <QScrollBar>
+#include <QTimer>
 #include <QCheckBox>
 #include <QSet>
 #include <QFormLayout>
@@ -524,7 +525,10 @@ void OllieKateView::onSessionKilled(const QString &session_id)
         m_chatView->clear();
         m_sessionLabel->setText("No session");
         m_cwdLabel->setText("");
-        refreshSessions();
+        // Defer session switch to let Qt finish processing the D-Bus signal.
+        // Calling render() synchronously here can crash because the QTextDocument
+        // is still tearing down resources from the clear() above.
+        QTimer::singleShot(0, this, &OllieKateView::refreshSessions);
     }
 }