Expo sdk 55 upgrade

[MarufHossain14]

Summary

Upgrades the app from Expo SDK 54 to SDK 55 and fixes the main regressions found during the upgrade across web rendering, navigation, routing structure, and page layout.

Main Changes

• Upgraded Expo / React Native dependencies to SDK 55-compatible versions
• Updated app.config.ts for SDK 55 compatibility
• Moved shared components out of app/ into components/
• Moved PostHog setup into lib/posthog.ts
• Fixed web/SSR issues caused by PostHog initialization
• Aligned React Navigation package versions with expo-router
• Fixed invalid nested link markup on web
• Fixed screen layout sizing and scrolling issues in tab pages
• Updated notification subscription cleanup for current Expo Notifications API
• Updated .gitignore for managed workflow (.idea/, /android, /ios)

Validation

Tested locally with:

• npx expo-doctor
• pnpm exec tsc --noEmit
• npx expo export --platform web

All passed.

Notes

• This branch assumes android/ is generated and should not stay committed.
• A follow-up may be needed to scope EAS Updates config away from local Expo Go development if remote update errors continue there.