Flutter Webview App & Admin

I need a Flutter-based application that wraps an existing website inside a WebView. While browsing, the user should be able to tap an “Add to My List” button that stores the current product or page in a personal list kept locally and synced to the back-end. This list must be easy to share via the standard share sheet so recipients without the app can open the shared URL directly in a browser.

Login is handled exclusively through social media, with Facebook and Google as the available providers. No email/password fallback is required.

Behind the scenes I will need a lightweight back-end (language and framework are up to you) together with an admin panel that lets me:
• manage registered users and their saved lists,
• edit or delete any user-generated content if needed, and
• view basic analytics and export periodic reports.

Please package the work so that I receive:
• the complete Flutter project ready for iOS, Android, and web,
• back-end source with REST or GraphQL endpoints that the app consumes,
• an admin panel (web) connected to the same back-end, and
• concise setup documentation so I can deploy everything on my own server.

Clean architecture, null-safe Dart, and well-commented code are expected. Let me know your proposed tech stack and estimated timeline when you respond.