I already have a working Flutter-based WebView browser app. This is NOT a new app development. I need an experienced Flutter developer to upgrade and extend the existing application. Update Scope: - The browser already opens websites via Google Search by default. - If a website fails to load due to: HTTP errors (403, 401, 451), Network errors (ERR_CONNECTION_RESET, ERR_CONNECTION_REFUSED, ERR_ADDRESS_UNREACHABLE), SSL errors (ERR_SSL_PROTOCOL_ERROR, Handshake Failure), DNS errors (ERR_NAME_NOT_RESOLVED), the app should automatically retry loading the website using a proxy. - The app is already connected to Firebase with an admin panel. - Proxy settings (domain, username, password) must be managed from the Firebase admin panel. - Any change made in the admin panel should reflect instantly in the browser app. - The proxy must work reliably with the existing WebView setup. Requirements: - Strong experience with Flutter and WebView - Proxy and network handling knowledge - Firebase integration experience - Ability to work with an existing codebase This is an update and system integration task for an existing browser app. Only experienced Flutter developers should apply.