djdaksh1122-spec/Flutter-App — reverse-engineered prompt

Build me a Flutter attendance app that works on Android, iPhone, web, and desktop if possible. I want people to be able to sign in securely, mark attendance, and have everything sync through Firebase. It should still work offline, save changes locally, and then upload them when the device reconnects.

Please include basic roles for normal users and admins, simple screens for login, attendance history, and attendance management. Make the data handling reasonably secure so people cannot fake timestamps, tamper with records, or read data they should not have access to. If SMS based login or verification fits the project, wire that up in a way that can work with Twilio.

Please leave the project in a runnable state with sample or dummy accounts, sensible test data, and clear setup notes so I can launch it without a lot of guessing. You can look up current Flutter and Firebase docs online if needed.