- Remove dead theme preset (no CSS, not in DevToolbar)
- Extract from closure → module-level export in lib/config/index.ts
- Extract helper in app/[...path]/page.tsx to deduplicate password gate check
- Extract inner component in app/page.tsx (was 4× inline in minimal/fullbleed/mosaic/split)
- Add 8 unit tests for buildSubpageGrid covering undefined, subset fields, layout fallback, and all fields