fn prompt_default_profile(project_dir: &Path) -> Result<(), CliError>Expand description
Interactive nudge to pick a default profile right after scaffolding.
Skipped silently in non-interactive contexts (JSON output, --quiet, or a
non-TTY stdin) so this never blocks CI. When skipped, the user can still
run mz-deploy profile set <name> later — we don’t want to re-explain
that on every script invocation.