The first checklist (Select Components) could silently auto-confirm its
defaults, swallowing the user's toggle: tui-install.sh runs right after the
long, mostly-unattended base install, and keystrokes buffered during that
wait were consumed by the script's very first read. Drain the tty before the
first prompt.
Also split the "shell" component into "shell" (tools/plugins/programs) and
a new "shellrc" (personal .bashrc/.zshrc/.vimrc), so the shell environment
can be installed without overwriting the user's rc files. shell-setup.sh
reads MARCHY_DEPLOY_SHELL_RC to gate the rc symlinks and now also deploys
.vimrc, which /etc/skel sync already expected but nothing ever created.
Removes the separate, easily-desynced "Shell Config for New Users" prompt
in favor of deriving /etc/skel behavior from the same shellrc choice, and
mirrors the removal in generate-answerfile.sh.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>