Simple Lag Fix

Added auto item clearing with countdown messages in chat.

Implemented mob limits per chunk to reduce server lag.

Added TPS monitor with customizable BossBar for OPs.

Added player-specific debug toggle for admins.

Added tab-completion for all /lagfix subcommands.

Added manual commands: /lagfix status, /lagfix clearitems, /lagfix reload, /lagfix tps, /lagfix debug.

Fully configurable: item clear intervals, item age, mob limits, blocked spawn reasons, TPS display.

Optimized performance for loaded chunks only to prevent server lag.