RGItemGuard | Control items in zones v1.6

• Significantly reduced the cost of inventory audits.
• Added inventory-state caching to skip redundant checks when nothing changed.
• Grouped consecutive inventory events into a single audit.
• Cached AdvancedEnchantments API discovery instead of repeating reflection for every item.
• Deferred custom display-name processing until an item matches a rule.
• Reduced allocations and main-thread work during item inspection.
• Preserved full detection for vanilla items, custom items, enchantments, containers, and slot-based rules.
• Added automatic cleanup of cached player data when players disconnect.