fix: remove sudo keepalive mechanism from installation scripts

scripts/setup_ros2_desktop.sh

@@ -8,15 +8,6 @@ export DEBIAN_FRONTEND=noninteractive
 
 PROGRESS() { echo "PROGRESS:$1:$2"; }
 
-# Keep sudo credentials alive throughout the installation so the build step that
-# follows (rosdep/colcon) does not trigger a password prompt inside the TUI.
-# Обновляем sudo-токен в фоне чтобы он не истёк за время установки и не запросил
-# пароль повторно во время rosdep/colcon внутри TUI.
-sudo -v
-( while true; do sudo -v; sleep 240; done ) &
-_SUDO_KEEPALIVE_PID=$!
-trap 'kill "$_SUDO_KEEPALIVE_PID" 2>/dev/null || true' EXIT
-
 PROGRESS 0 "Checking dpkg state..."
 echo "Checking dpkg state..."
 sudo dpkg --configure -a