Goal

Add a loop-sandbox subsection to QUICKSTART. The package is published and used by loop-action, but newcomers may only see audit/init.

Files

• docs/QUICKSTART.md — short subsection after worktree / safety tools
• Cross-link tools/loop-sandbox/README.md

Acceptance criteria

• Explains ephemeral worktree isolation in one paragraph
• Shows npx @cobusgreyling/loop-sandbox run -- <cmd> (and optional --shell)
• Notes Windows ENOENT auto-retry for npm .cmd shims (no need to force --shell for npx)
• Links safety / review of patches before apply

Estimated time: ~25 minutes

Comment "I'll take this" to get assigned.