商店分頁系統 / Shop Pagination System
- 新增分頁導航 / Added Pagination Navigation**
- 添加了「上一頁」和「下一頁」按鈕，使用箭頭材質 / Added "Previous" and "Next" page buttons with arrow materials
- 商店標題現在顯示當前頁面信息（例如："掉落物商店 - 第1頁"）/ Shop title now displays current page info (e.g., "Drop Shop - Page 1")
- 每頁顯示45個不同物品，保留最後一行給控制按鈕 / Each page displays 45 different items, reserving the last row for control buttons
- 智能按鈕顯示：只在有可用頁面時顯示導航按鈕 / Smart button display: navigation buttons only appear when pages are available
- 系統會記住每個玩家當前瀏覽的頁面 / System remembers each player's current page

無限量物品存儲系統 / Unlimited Item Storage System
- 突破Minecraft堆疊限制 / Breaking Minecraft Stack Limits
- 使用新的 `itemCounts` 映射存儲 `Long` 類型數量，支持超過64個物品 / Uses new `itemCounts` mapping to store `Long` type quantities, supporting more than 64 items
- ItemStack只存儲1個作為模板，實際數量單獨記錄 / ItemStack stores only 1 as template, actual quantities recorded separately
- 保證所有物品都會被記錄，不會因數量限制而丟失 / Guarantees all items are recorded without loss due to quantity limits
- 防止插件因數量問題崩潰 / Prevents plugin crashes due to quantity issues

用戶界面改進 / User Interface Improvements
- 重新設計的控制按鈕布局 / Redesigned Control Button Layout
- 位置45：上一頁按鈕 / Slot 45: Previous page button
- 位置46：刷新按鈕 / Slot 46: Refresh button
- 位置49：信息按鈕（顯示頁面和數量信息）/ Slot 49: Info button (displays page and quantity info)
- 位置52：清空商店按鈕（管理員專用）/ Slot 52: Clear shop button (admin only)
- 位置53：下一頁按鈕 / Slot 53: Next page button

- 大數字格式化顯示 / Large Number Formatting
- 自動將大數字格式化為易讀形式 / Automatically formats large numbers for readability
- 例如：1,500 → 1.5K，2,300,000 → 2.3M，1,200,000,000 → 1.2B / Examples: 1,500 → 1.5K, 2,300,000 → 2.3M, 1,200,000,000 → 1.2B

技術改進 / Technical Improvements

數據結構優化 / Data Structure Optimization
- 添加 `Map<Player, Integer> playerPages` 來跟踪玩家頁面狀態 / Added `Map<Player, Integer> playerPages` to track player page states
- 添加 `Map<String, Long> itemCounts` 來存儲大數量 / Added `Map<String, Long> itemCounts` to store large quantities
- 優化了物品ID生成和匹配邏輯 / Optimized item ID generation and matching logic

️ 穩定性增強 / Stability Enhancements
- 改進了錯誤處理和邊界檢查 / Improved error handling and boundary checks
- 更新了購買邏輯以使用新的數量系統 / Updated purchase logic to use new quantity system
- 保持了向後兼容性，舊API方法仍然可用 / Maintained backward compatibility, old API methods still available

方法更新 / Method Updates
- `addItemsToShop()`: 更新為使用新的存儲系統 / Updated to use new storage system
- `openShop()`: 添加分頁參數支持 / Added pagination parameter support
- `purchaseItem()`: 更新為使用 `itemCounts` 而非 ItemStack 數量 / Updated to use `itemCounts` instead of ItemStack amounts
- `getItemAmount()`: 重寫以支持大數量計算 / Rewritten to support large quantity calculations
- 新增 `formatLargeNumber()`: 格式化大數字顯示 / Added `formatLargeNumber()`: formats large number display
- 新增 `getPlayerPage()`: 獲取玩家當前頁面 / Added `getPlayerPage()`: gets player's current page

用戶體驗改進 / User Experience Improvements

交互優化 / Interaction Optimization
- 分頁按鈕點擊響應更加流暢 / Smoother pagination button click responses
- 刷新商店時保持當前頁面位置 / Maintains current page position when refreshing shop
- 清空商店後自動返回第一頁 / Automatically returns to first page after clearing shop
- 改進的庫存不足提示信息 / Improved insufficient stock notification messages