🤖 The app now remembers your chats on your device, so reloading opens
instantly — no more waiting for everything to re-download, and recently
visited chats open on the spot even with a shaky connection. What's kept
locally is exactly as locked as what the server holds: your messages stay
sealed, and they're cleared if you sign out or leave a group. The loading
scene now only greets you on your very first visit.