Changes

• Diamond behavior is now event-driven: mined diamonds carry an "unpicked" tag and are converted and triggered on inventory interactions (click/drag/close), pickup, or full-inventory takeover, instead of scanning the player's inventory every tick
• Converted diamonds become plain diamonds without NBT markers, restoring vanilla auto-stacking
• Diamonds can still be picked up when the inventory is full: processed up to the remaining capacity (empty slots × 64 + plain diamond stack space), with the overflow left on the ground
• Removed the per-tick diamond scan from GameStateManager