Maintain docs/RISK_REGISTER.md, the living, append-only list of every deferred item, interim shortcut, and open architecture decision for this project. Use when a shortcut is taken, a decision is postponed, a follow-up is filed, or an existing entry is actually resolved. DO NOT use for accepted, finalized architecture decisions (use adr-capture instead), for session-local working notes that don't need to survive across the team (use context-file / the local scratch-notes directory instead), or for anything that must stay confidential (the register is a committed, team-visible doc). Triggers: 'add to risk register', 'log this as a risk', 'track this shortcut', 'this is a known gap', 'mark risk #N resolved', 'what's on the risk register', 'what's still open'.