I'm looking for an experienced developer to create a web wrapper app for both iOS and Android platforms. The app will require user authentication and should include the following functionalities: - Push Notifications: Keep users engaged with timely updates. - Custom Navigation Menu: Tailor the app's navigation to enhance user experience. - File Upload: Allow users to upload files within the app. Ideal skills and experience: - Proficiency in developing cross-platform mobile apps. - Experience with user authentication systems. - Familiarity with implementing push notifications and custom navigation menus. Please provide samples of similar work done and an estimated timeline for completion.