feat: explore tab, React Query data layer, programs, sync, analytics, testing infrastructure

- Replace browse tab with Supabase-connected explore tab with filters
- Add React Query for data fetching with loading states
- Add 3 structured programs with weekly progression
- Add Supabase anonymous auth sync service
- Add PostHog analytics with screen tracking and events
- Add comprehensive test strategy (Vitest + Maestro E2E)
- Add RevenueCat subscription system with DEV simulation
- Add i18n translations for new screens (EN/FR/DE/ES)
- Add data deletion modal, sync consent modal
- Add assessment screen and program routes
- Add GitHub Actions CI workflow
- Update activity store with sync integration

.gitignore

@@ -41,3 +41,14 @@ app-example
 # generated native folders
 /ios
 /android
+
+# Maestro
+.maestro/screenshots/
+.maestro/recordings/
+.maestro/env.local.yaml
+
+# Test coverage
+coverage/
+
+# Node compile cache
+node-compile-cache/