- Add Leaflet map tab in public/index.html with CARTO dark tiles, category
toggles, vote-count markers, and external venue search
- Extract seed data to seed-data.js with CATEGORY_META, buildSeedData(),
mergeSeedData() helpers
- Refactor server.js: approvedOptionsWithVoteSummary(), buildRealtimeSnapshot(),
createUserOption() helpers; Yelp API proxy at /api/yelp; /api/budgets endpoint
- Extract inline seed data from server.js to seed-data.js module
- Add budgetScenarios and priceUpdatedAt to realtime snapshot