build-packagelisted

# Build the next work package 1. Read `BUILD-PROMPT.md` in full. It is the contract for this session; its §3 invariants and §7 prohibitions override any instinct you have. 2. Open `docs/PROGRESS.md`. If missing, create it seeded with the M0–M7 checklist from `docs/IMPLEMENTATION.md` and the M0/M1 packages from BUILD-PROMPT §5. Find the first unchecked package. If the current milestone has no package list yet, derive one per BUILD-PROMPT §5 ("M2 → M7") and write it into PROGRESS.md before coding. 3. Read only the docs BUILD-PROMPT §2 maps to this package. 4. Execute the working loop (BUILD-PROMPT §4). Hard rules: - `npm run typecheck && npm run lint && node scripts/check-invariants.cjs && npm run test:coverage && node scripts/check-coverage.cjs` green before any commit — BUILD-PROMPT §4's TEST line (since M8.0 the suite runs once, under coverage, and the seam rule's two checks run with it). - Tests owed by the package (TEST-STRATEGY §2 mapping) are part of the package. - Evidence (command + observed result) goes in the commit description. - 3 failed distinct attempts on a blocker → stop, record it, report (don't hack around). 5. Tick the package in `docs/PROGRESS.md` with a one-line evidence note; log any minor choices in `docs/DECISIONS-LOG.md`; queue must-ask questions for the Architect. 6. End with the session report format from BUILD-PROMPT §9. Package too big mid-flight (> ~10 files)? Split it in PROGRESS.md and do the first half properly rath