fix: correct connect/disconnect button state on connection lifecycle

- Enable disconnect button immediately when connect is clicked, so the
  user can cancel without waiting for the StateConnecting IPC event.
- Disable disconnect button on all error paths in the connect goroutine
  to restore the default disconnected button state.
- Capture ipcClient once at eventLoop start instead of re-reading every
  iteration, preventing a second onConnect call from making the old
  event loop jump to the new client and consume events concurrently.
- In eventLoop recv error recovery, only reset button states if the
  current ipcClient still matches the captured one, so a stale
  disconnection does not clobber the state of a newer session.
- Disable connect button in StateReconnecting case (was missing).
- Remove WriteOK from daemon startSession: the StateConnecting event
  already serves as the implicit acknowledgment; the OK response was
  being read by eventLoop as a no-op event, adding unnecessary noise.

internal/daemon/daemon.go

@@ -155,7 +155,6 @@ func (d *daemon) startSession(conn net.Conn, req ipc.Request) {
 		d.session = nil
 		return
 	}
-	_ = ipc.WriteOK(conn)
 }
 
 func (d *daemon) stopSession() {

internal/ui/view.go

@@ -75,6 +75,7 @@ func (a *App) onConnect() {
 	}
 
 	a.connectBtn.Disable()
+	a.disconnectBtn.Enable()
 	a.stateLabel.SetText(i18n.T("StateConnecting"))
 
 	go func() {
@@ -85,6 +86,7 @@ func (a *App) onConnect() {
 				showError(i18n.T("DlgDaemonError"), err.Error(), a.window)
 				a.stateLabel.SetText(i18n.T("StateDisconnected"))
 				a.connectBtn.Enable()
+				a.disconnectBtn.Disable()
 			})
 			return
 		}
@@ -102,6 +104,7 @@ func (a *App) onConnect() {
 					a.window)
 				a.stateLabel.SetText(i18n.T("StateDisconnected"))
 				a.connectBtn.Enable()
+				a.disconnectBtn.Disable()
 			})
 			return
 		}
@@ -121,6 +124,7 @@ func (a *App) onConnect() {
 				showError(i18n.T("DlgIPCError"), err.Error(), a.window)
 				a.stateLabel.SetText(i18n.T("StateDisconnected"))
 				a.connectBtn.Enable()
+				a.disconnectBtn.Disable()
 			})
 			return
 		}
@@ -146,16 +150,21 @@ func (a *App) onDisconnect() {
 
 // eventLoop reads IPC events from the daemon and updates the UI.
 func (a *App) eventLoop() {
-	for {
 	a.mu.Lock()
 	client := a.ipcClient
 	a.mu.Unlock()
 	if client == nil {
 		return
 	}
+
+	for {
 		ev, err := client.Recv()
 		if err != nil {
 			fyne.Do(func() {
+				a.mu.Lock()
+				current := a.ipcClient
+				a.mu.Unlock()
+				if current == client {
 					a.stateLabel.SetText(i18n.T("StateDisconnected"))
 					a.ipLabel.SetText(i18n.T("IpNone"))
 					a.uptimeLabel.SetText(i18n.T("UptimeNone"))
@@ -163,6 +172,7 @@ func (a *App) eventLoop() {
 					a.txLabel.SetText(i18n.T("TxZero"))
 					a.connectBtn.Enable()
 					a.disconnectBtn.Disable()
+				}
 			})
 			return
 		}
@@ -201,6 +211,7 @@ func (a *App) applyState(state string) {
 		a.disconnectBtn.Enable()
 	case stats.StateReconnecting:
 		a.stateLabel.SetText(i18n.T("StateReconnecting"))
+		a.connectBtn.Disable()
 		a.disconnectBtn.Enable()
 	case stats.StateDisconnected:
 		a.stateLabel.SetText(i18n.T("StateDisconnected"))