Add authentication, Firebase integration, and web deployment

- Implement web authentication with access key for security
- Add Firebase Crashlytics for Android app monitoring
- Configure nginx for serving Flutter web app at docrec.zackchew.xyz
- Update Android package name and app icons
- Add backend authentication views and user login functionality
- Create settings screen with access control for web
- Add APK server for downloading Android builds
- Include deployment configuration and documentation

🤖 Generated with Claude Code (https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>