v0.2.7: Add sudo, mousepad, and useful CLI tools to container

- Install mousepad text editor (lightweight XFCE editor)
- Install sudo with NOPASSWD for compeek user so the agent can
  install additional packages at runtime (sudo apt install -y ...)
- Add wget, jq, zip/unzip to pre-installed CLI tools
- Update system prompt to accurately list available apps and
  confirm passwordless sudo access
- Update preset goal to reference mousepad directly