ROADMAP.md was named as a destination in two places but never created,
indexed, or read back. Add the convention to how-i-work.md, note it after
the README decision tree and in the loads-when table, give it a row in the
portability layer table, make the retrofit prompt create it, and have
handoff seed it and pull from it when Current state's next steps run thin.
Move the handoff checklist body into guides/handoff.md as plain prose,
and replace the Claude command with a thin wrapper that reads the guide,
matching the full-eval pattern.