refactor: 重構 VendorProduct API 與新增進貨單重複檢查前端邏輯

1. 將 VendorProductController 中的 Eloquent 關聯操作改為透過 ProcurementService 使用 DB 操作，解除跨模組 Model 直接依賴。
2. ProcurementService 加入 vendor product 的資料存取方法。
3. 進貨單建立前端 (GoodsReceipt/Create.tsx) 新增重複進貨檢查與警告對話框邏輯。

app/Modules/Inventory/Routes/web.php

@@ -179,6 +179,9 @@ Route::middleware('auth')->group(function () {
         Route::get('/goods-receipts', [\App\Modules\Inventory\Controllers\GoodsReceiptController::class, 'index'])->name('goods-receipts.index');
         Route::get('/goods-receipts/create', [\App\Modules\Inventory\Controllers\GoodsReceiptController::class, 'create'])->middleware('permission:goods_receipts.create')->name('goods-receipts.create');
         Route::get('/goods-receipts/{goods_receipt}', [\App\Modules\Inventory\Controllers\GoodsReceiptController::class, 'show'])->name('goods-receipts.show');
+        Route::post('/goods-receipts/check-duplicate', [\App\Modules\Inventory\Controllers\GoodsReceiptController::class, 'checkDuplicate'])
+            ->middleware('permission:goods_receipts.create')
+            ->name('goods-receipts.check-duplicate');
         Route::post('/goods-receipts', [\App\Modules\Inventory\Controllers\GoodsReceiptController::class, 'store'])->middleware('permission:goods_receipts.create')->name('goods-receipts.store');
         
         // 點收提交路由