fix(enter): re-prompt instead of aborting on invalid input

[CheapFuck]

Summary

When towel enter finds no towel container, it asks whether to create one. Answering with anything other than yes/no (a typo) aborts the command instead of asking again.

Root cause

The prompt is a while builtin read loop, but an unconditional exit 1 sits after the case, inside the loop body:

while builtin read -rp "Create it now? yes|No:"; do
    case "$REPLY" in
    y | yes | Y | Yes | YES) towel create; break ;;
    n | no | N | No | NO)    exit ;;
    *)                       echo "Invalid input." 1>&2 ;;
    esac
    exit 1   # <- always runs for the '*' branch
done

The yes branch breaks and the no branch exits, so the only path that reaches exit 1 is the * (invalid) branch. The loop can therefore never iterate — a single invalid answer prints Invalid input. and exits with status 1.

Fix

Remove the stray exit 1. Invalid input now falls through and the loop re-prompts as intended; yes/no behaviour is unchanged.

Testing

• shellcheck -x across all scripts: pass
• shfmt -d across all scripts: pass

Related to #13 (the container-existence check it asks for is already in place; this fixes the remaining re-prompt bug in that flow). Happy to adjust the linkage if you'd prefer.