feat: add deals feature with database seeding, backend API, and inter…

[yashmitb]

feat: add deals feature with database seeding, backend API, and interactive UI component

Changes

Added a full Deals & Offers page for logged-in UCSD students, backed by a Supabase deals table seeded from multiple open-source student discount databases.

• Database: Created deals table with 268 unique student deals across 9 categories (Software, Cloud, Education, Productivity, Shopping, Entertainment, AI, Music, UCSD Exclusive). Added link_status column populated by a link validation script that HEAD-checks all 268 URLs.
• Backend: Added GET /deals endpoint with optional ?category= filter, returning deals sorted by UCSD-specific first.
• Frontend: New Deals tab (5th tab, pricetag icon) using the existing Tamagui design system — matches Home tab layout with Screen, Card, SectionTitle, and AppText primitives.
  • Navy header with total/free/UCSD-exclusive stat chips
  • Animated search bar (border color transitions on focus)
  • Horizontal category filter pills with spring bounce animation on press
  • DealCard components with staggered fade+slide entrance animations, color-coded category/badge chips, UCSD exclusive gold strip, and ✓ Verified / Unchecked link status badge
• Seeding: Single combined seed script (seed_deals_all.ts) merges all three sources with name-based deduplication (curated data takes priority).
• Link validation: validate_links.ts — runs parallel HEAD requests against all deal URLs, marks each as verified, broken, or unchecked in the DB. Re-runnable anytime.

Testing

• Ran seed_deals_all.ts — confirmed 268 deals inserted cleanly across all categories.
• Ran validate_links.ts — 224 verified, 18 broken, 26 unchecked out of 268.
• Tested GET /deals and GET /deals?category=UCSD via curl — correct results, UCSD deals sorted first.
• Verified Deals tab renders, search filters correctly, category pills animate, and "Get Deal" opens the correct URL.