I need a mobile application that will take every lecture posted inside my private Telegram groups, copy it over, and make it permanently available inside the app even if the files are later deleted or the groups disappear. The finished product must run smoothly on both Android and iOS. Core workflow • First-time sync: pull all existing lectures (audio, video, PDF, any media) from each of my specified Telegram groups. • Ongoing sync: new items added in those groups should flow into the app automatically. • Once stored, the files must play or open directly in the app with no outbound call to Telegram or the original message link. Organisation & interface Inside the app I want a simple “Groups” screen; tapping a group opens its full lecture list. Within each group, users can search by file name, see the date added, and download for offline access. A clean media player / PDF viewer is essential. What I expect to receive 1. Production-ready Android (AAB/APK) and iOS (IPA/TestFlight) builds. 2. Source code with clear instructions to rebuild. 3. Any lightweight backend or local database necessary to cache and serve the files. 4. Brief hand-off documentation showing how to add or remove groups in the future and how the sync schedule works. If you have tackled Telegram content migration or cross-platform media apps before, let me know; that experience will be invaluable.