Prep Martha Jun Wk1 (TypeScript + content collections)

## Must complete by Monday June 1 sync - [x] Write TypeScript for centralized data guide — `guide-typescript-data.md` - [ ] Create a reference project showing the content collection pattern (services collection with 3 sample entries + siteConfig.ts) — Martha clones this to see the pattern before building - [ ] Review Martha's Phase 1 gate (end of May) results — confirm she passed, note areas to watch - [ ] Set Astro project template with TypeScript enabled for Martha: `bun create astro@latest -- --template minimal` and verify it works - [ ] Prepare Monday sync agenda: intro TypeScript (10 min demo of autocomplete + error catching), assign Mock Client #2 brief