Add Face Login (Face ID / facial recognition) for quick sign-in

Description: Please add the option to log in to Songer using face recognition (for example, Face ID on supported devices). Problem: Right now, signing in requires typing an email and password or going through a social login. This can be slow and inconvenient, especially on mobile, and it adds friction when returning to create new tracks. Proposed solution: - Add a "Log in with Face ID" option on the login screen for supported devices - Let users enable or disable face login in their account settings - Keep email and password (or social login) available as a fallback Benefits: - Faster, one-tap access to the platform - Less friction for returning users - Added convenience on mobile devices - Familiar sign-in experience that many users already use in other apps Use case: As a frequent user, I want to open Songer and sign in with my face, so I can get back to creating music without typing my credentials every time.