init static method
Implementation
static Future<void> init() async {
_prefs = await SharedPreferences.getInstance();
// Preload the token from the Keychain/Keystore into the sync cache.
try {
_tokenCache = await _secure.read(key: _kSecureToken);
} catch (_) {
_tokenCache = null; // secure storage unavailable — fail closed (no token)
}
}