Reliability: onDisable hologram cleanup + safer UUID persistence

[Geph]

Summary

Several reliability gaps around lifecycle and saves:

1. No onDisable cleanup — DecentHolograms entities / click handlers may linger across /reload
2. Async UUID lookup — save path can call Bukkit.getPlayer(name).getUniqueId() after the player has left → NPE
3. Expiration load filter — verify load query truly means “not expired” (expiration > now)

Suggested approach

• Delete/unregister holograms and clear click maps in onDisable
• Capture UUID from the Player at create time and pass it into the async save
• Double-check SQL load predicates for expired rows