[1] Added per-player toggle system with unified /jc toggle command (fast crystal, totem particles, explosion particles, explosion sounds, chainmail kit)
[2] Implemented invisibility chat hide feature to block/filter messages from invisible players
[3] Fixed empty action bar spam by sending empty message only once when clearing
[4] Added proper PacketEvents-based packet interception for totem and explosion effects
[5] Fixed fast crystal toggle double-toggle sync bug by centralizing state management
[6] Added configurable chainmail kit on respawn with toggle support