Prep Martha Jun Wk3 (Biome + full build review)

## Must complete by Monday June 15 sync - [x] Write Biome setup guide — `guide-biome-setup.md` - [ ] Review Martha's siteConfig + content collections from Wk2 — verify no hardcoded strings remain - [ ] Set up webhook URL for GreenScape quote form (n8n → mock CRM) - [ ] Prepare Monday sync: quick Biome demo (run check, fix, format), assign full build