17 functions: logging (info/warn/error/success/step/phase_header),
env management (load_env/save_env_var/require_vars), SSH wrappers
(ssh_exec/ssh_check/scp_to), API wrappers (gitea_api/gitea_backup_api/
github_api), template rendering, and polling (wait_for_http/wait_for_ssh).
All logs go to stderr, JSON data to stdout. Shellcheck clean.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
