Implement Zero-Tap-Sign-In for AnkiWeb

> The [Zero-Tap Sign-In](https://support.google.com/googleplay/android-developer/answer/17492799#zero-tap_sign-in_restoration) standard will require any app supporting user sign-in, optional or mandatory, to automatically restore a user's sign-in state when they move from one Android device to another with the [Android Restore Credentials API](https://developer.android.com/identity/sign-in/restore-credentials). This API ensures that when a user opens your app on their new Android device for the very first time, they are instantly recognized and securely signed in without additional taps.
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> Starting in April 2027, Google Play will require apps to meet the Zero Tap Sign-In requirement to maintain full publishing capabilities and optimal visibility in the Play Store.

https://android-developers.googleblog.com/2026/08/app-quality-memory-optimization-secure-onboarding.html