- Create AGENTS.md: comprehensive agent guide covering architecture,
data flow, error bar convention (90% intervals), D3 usage patterns,
null safety pitfalls, deployment checklist, and related repos
- Update HANDOFF.md: mark CORS as resolved, document chart improvements
(Chart 5 ridgeline rewrite with synthetic draws + smooth rendering)
- Refresh README.md: accurate tech stack (D3 v7), updated file structure
with new chart files, corrected API endpoint table
jared