handoff — compact this session for a fresh agent

Produce a standalone document a cold agent can act on with zero prior context. (Distilled in our own way from Matt Pocock's handoff, MIT.)

Where to write it

Save to the OS temp directory (%TEMP% on Windows, $TMPDIR / /tmp on macOS/Linux) — never the workspace/repo. Handoff docs are ephemeral; they don't belong in git.

Skeleton

# Handoff — <one-line topic>

## Goal
What we're trying to achieve (the destination, not the history).

## Current status
Where things stand now; what works, what's half-done.

## Key decisions & rationale
Choices already made and *why* — so the next agent doesn't relitigate them.