Fix UART hang after master restart from the dashboard.

ReadFrame now returns on serial timeout instead of looping forever, and
serve closes and reopens the port after a master reboot so polling and
API commands can resume.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/client_api.go

@@ -417,9 +417,16 @@ func (m *managedSerial) FindMe(clientID uint32) error {
 }
 
 func (m *managedSerial) Restart(clientID uint32) error {
-	return m.withPort(func(sp *serialPort) error {
+	err := m.withPort(func(sp *serialPort) error {
 		return runRestartClient(sp, clientID)
 	})
+	if err != nil {
+		return err
+	}
+	if clientID == 0 {
+		m.recoverAfterMasterRestart()
+	}
+	return nil
 }
 
 func (s *serialPort) ledRingProgress(req *pb.LedRingProgressRequest) (*pb.LedRingProgressResponse, error) {