kate: add connection state tracking and auto-recovery

Adds a heartbeat timer (5s interval) that pings the 9P server with a
cheap read. If the server goes down, the status bar turns red showing
'disconnected'. When it comes back, the plugin reconnects and
re-selects the agent for the current project.

Status bar now shows connection state:
- Red '✗ disconnected' — server unreachable
- Gray '○ no agent' — connected but no agent selected
- Green '● kate/ID' — connected with active agent

kate/ollie_kate.cpp

@@ -60,12 +60,19 @@ OllieKateView::OllieKateView(OllieKatePlugin *plugin, KTextEditor::MainWindow *m
     , m_plugin(plugin)
     , m_mainWindow(mainWindow)
     , m_9p(new Lib9pClient(this))
+    , m_heartbeatTimer(new QTimer(this))
 {
     // Connect to 9P server
-    if (!m_9p->connectDefault()) {
+    m_connected = m_9p->connectDefault();
+    if (!m_connected) {
         qWarning() << "Ollie: failed to connect to 9P server:" << m_9p->lastError();
     }
 
+    // Heartbeat timer — detect server death and reconnect
+    m_heartbeatTimer->setInterval(5000);
+    connect(m_heartbeatTimer, &QTimer::timeout, this, &OllieKateView::heartbeat);
+    m_heartbeatTimer->start();
+
     // Status bar indicator
     if (auto *win = qobject_cast<QMainWindow *>(m_mainWindow->window())) {
         m_statusLabel = new QLabel();
@@ -120,6 +127,7 @@ OllieKateView::OllieKateView(OllieKatePlugin *plugin, KTextEditor::MainWindow *m
 
 OllieKateView::~OllieKateView()
 {
+    m_heartbeatTimer->stop();
     delete m_ghost;
     if (m_statusLabel) {
         delete m_statusLabel;
@@ -229,10 +237,46 @@ QString OllieKateView::agentPath() const
 void OllieKateView::updateStatusLabel()
 {
     if (!m_statusLabel) return;
-    if (m_agentId.isEmpty()) {
+    if (!m_connected) {
+        m_statusLabel->setText(QStringLiteral("✗ ollie: disconnected"));
+        m_statusLabel->setStyleSheet(QStringLiteral("color: red; padding: 0px 4px;"));
+    } else if (m_agentId.isEmpty()) {
         m_statusLabel->setText(QStringLiteral("○ ollie: no agent"));
+        m_statusLabel->setStyleSheet(QStringLiteral("color: gray; padding: 0px 4px;"));
     } else {
         m_statusLabel->setText(QStringLiteral("● ollie: kate/") + m_agentId);
+        m_statusLabel->setStyleSheet(QStringLiteral("color: green; padding: 0px 4px;"));
+    }
+}
+
+// --- Connection Recovery ---
+
+void OllieKateView::heartbeat()
+{
+    // Try a cheap read to verify daemon is alive
+    if (!m_9p->isConnected()) {
+        if (!m_9p->connectDefault()) {
+            if (m_connected) {
+                m_connected = false;
+                updateStatusLabel();
+            }
+            return;
+        }
+    }
+
+    QByteArray result = m_9p->read(QStringLiteral("help"));
+    bool alive = !result.isEmpty();
+
+    if (alive && !m_connected) {
+        // Recovered — re-establish state
+        m_connected = true;
+        selectAgentForProject();
+        updateStatusLabel();
+    } else if (!alive && m_connected) {
+        // Lost connection
+        m_connected = false;
+        m_9p->disconnect();
+        updateStatusLabel();
     }
 }
 

kate/ollie_kate.h

@@ -12,6 +12,7 @@
 #include <QLabel>
 #include <QAction>
 #include <QEvent>
+#include <QTimer>
 
 #include "lib9pclient.h"
 
@@ -60,6 +61,7 @@ protected:
 
 private slots:
     void onProjectChanged();
+    void heartbeat();
 
 private:
     // Actions
@@ -89,7 +91,9 @@ private:
 
     QString m_sessionId;
     QString m_agentId;
+    bool m_connected = false;
 
+    QTimer *m_heartbeatTimer;
     QLabel *m_statusLabel = nullptr;
     QPointer<OllieGhostProvider> m_ghost;
     bool m_ghostPrefix = false;