v1.8.1

Help output reformatted to go-tool style

• Top-level menu now renders like go help: a Usage: block, a tab-indented "The commands are:" list, and a "Use "prog help "" footer.
• Per-command help shows a terse columnar flag table: name · alias · [type] · [ore*] attrs · (default) · help, all on one line.
• version is now a one-line banner.
• Example rewritten to demonstrate env.Commands dispatch with a graceful serve subcommand; readme updated to match.