gui/plasmoid: show error dialog on CreateSession failure

Adds errorOccurred signal to OllieDBusClient, emitted when
CreateSession (or other async calls) fail. GUI shows a modal
dialog; plasmoid shows a passive notification.

gui/main.qml

@@ -549,6 +549,24 @@ ApplicationWindow {
                 mainContent.panes[idx].sessionId = dbus.activeSessionId
             }
         }
+        function onErrorOccurred(message) {
+            errorDialog.text = message
+            errorDialog.open()
+        }
+    }
+
+    Dialog {
+        id: errorDialog
+        title: "Error"
+        modal: true
+        anchors.centerIn: parent
+        standardButtons: Dialog.Ok
+        property alias text: errorLabel.text
+        Label {
+            id: errorLabel
+            wrapMode: Text.Wrap
+            width: parent.width
+        }
     }
 
     // --- Process Manager Window ---

plasmoid/contents/ui/main.qml

@@ -14,6 +14,13 @@ PlasmoidItem {
     // Convenience alias
     readonly property var dbus: Ollie.OllieDBusClient
 
+    Connections {
+        target: dbus
+        function onErrorOccurred(message) {
+            root.Plasmoid.showPassiveNotification(message, 5000, "Error")
+        }
+    }
+
     FolderDialog {
         id: folderDialog
         title: "Choose working directory"

plasmoid/plugin/olliedbusclient.cpp

@@ -270,9 +270,17 @@ void OllieDBusClient::onFetchConfigFinished(QDBusPendingCallWatcher *watcher)
 QString OllieDBusClient::createSession(const QString &cwd)
 {
     QString dir = cwd.isEmpty() ? QDir::homePath() : cwd;
-    // Use asyncCall — we'll pick up the new session via the SessionCreated signal
-    m_iface->asyncCall("CreateSession", dir, QString(), QString(), QString("default"), QString());
-    return QString();  // ID not available synchronously; signal will trigger refresh
+    auto *watcher = new QDBusPendingCallWatcher(
+        m_iface->asyncCall("CreateSession", dir, QString(), QString(), QString("default"), QString()),
+        this);
+    connect(watcher, &QDBusPendingCallWatcher::finished, this, [this](QDBusPendingCallWatcher *w) {
+        QDBusPendingReply<QString> reply = *w;
+        if (reply.isError()) {
+            emit errorOccurred(reply.error().message());
+        }
+        w->deleteLater();
+    });
+    return QString();
 }
 
 void OllieDBusClient::createSessionWithDialog()

plasmoid/plugin/olliedbusclient.h

@@ -74,6 +74,7 @@ signals:
     void chatAppended(const QString &sessionId, int offset, const QString &text);
     void processDetached(const QString &sessionId);
     void processExited(const QString &sessionId, int pid, int exitCode);
+    void errorOccurred(const QString &message);
 
 private slots:
     void onSessionCreated(const QString &session_id);