## Project Rules
- Use existing patterns
- No refactors unless explicitly requested
- All changes must keep tests passing
- Prefer small, reviewable commits
- All `cmake --build` commands must use the `-j4` option for parallel building.
- after a task, a 'big' final commit should contain a short handoff tag like "handoff(Gemini):..." if you're gemini-cli, or "handoff(Claude): ..." if you're claude-code.