The token moves from flutter_secure_storage into JellyfinTokens.kt: a
file per person in the no-backup folder, sealed with AES-GCM under a key
of Android's Keystore, the person's ID as associated data, so that the
music job to come can read it as the app does. A token the keyring held
is moved over as it is first read.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>