Set up /app/warn.sh to hook into Bash's PROMPT COMMAND and warn users when they enter directories that match…

Set up /app/warn.sh to hook into Bash's PROMPT COMMAND and warn users when they enter directories that match…: a task in rts-1k-rootless-apptainer: RTS-1K: offline rootless Apptainer release (Harbor dataset). What the agent is asked, how it is graded, what it runs in, and its files.