Replace validate_env() with preflight_check() that verifies all factory
requirements before init proceeds:
- Required tools: claude, tmux, git, jq, python3, curl (hard errors)
- Claude Code authentication via claude auth status
- Codeberg auth: CODEBERG_TOKEN or ~/.netrc, verified with API call
- Codeberg SSH access: verified with ssh -T git@codeberg.org
- Optional: docker (warn only)
- Clear error messages with install hints for each missing tool
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>