Handoff - session handoff bundle

Compress the current Claude Code session into a portable markdown bundle the receiver can paste into a different session (same mac, different machine, claude.ai, future-you) and resume with zero context loss. Default voice - the receiver is already mid-work; the bundle leads with tasks to absorb into their existing todo list, decisions/git/in-flight/cold-start map are opt-in below. Lands as research/events/session-YYYY-MM-DD-<slug>/README.md in ZAO repos, ~/.zao/handoff/<slug>/ elsewhere. Pushes summary to Bonfire (best-effort). Auto-clipboards the bundle. Use when the user types /handoff, says "save my context", "summarize this session", "hand this off to another termina…