initUser method
Initialize user data asynchronously. Should be called early in startup.
Implementation
Future<void> initUser() async {
if (_emailFetched || _emailFetchPromise != null) return;
_emailFetchPromise = _getEmailAsync();
_cachedEmail = await _emailFetchPromise;
_emailFetched = true;
_emailFetchPromise = null;
_cachedCoreUserData = null; // Clear memoization
}