Keymap selection was unreachable because user input ran after pacman/partition
steps that could fail under set -e. Move the entire user input block (kernel,
hostname, username, encryption, keymap) to before lsblk and drive selection.
Also remove the redundant live-env keymap section (launch.sh handles that).
Drop exec from .zlogin so quitting the installer returns to a bash shell
instead of ending the session.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>