[FIX] 徹底修復商品管理分頁參數洩漏與 UI 狀態不一致問題

1. 隔離商品列表與分類管理的搜尋參數（product_search / category_search）。
2. 隔離商品列表與分類管理的公司篩選參數（product_company_id / category_company_id）。
3. 優化分頁切換邏輯，切換 Tab 時自動清理 URL 參數，解決標籤殘留問題。
4. 修復 searchable-select 組件因屬性傳遞錯誤導致的 500 Internal Server Error。
5. 統一各分頁「公司篩選」Placeholder 為「所有公司」。
6. 完成分類管理搜尋框的多語系支援（新增 Search categories... 翻譯鍵值）。
7. 優化分頁器 (Pagination) 樣式以符合極簡奢華風規範。

app/Http/Controllers/Admin/ProductController.php

@@ -19,12 +19,16 @@ class ProductController extends Controller
     public function index(Request $request)
     {
         $user = auth()->user();
-        $query = Product::with(['category.translations', 'translations', 'company']);
+        $tab = $request->input('tab', 'products');
+        $per_page = $request->input('per_page', 10);
+        
+        // Products Query
+        $productQuery = Product::with(['category.translations', 'translations', 'company']);
         
         // 搜尋
-        if ($request->filled('search')) {
-            $search = $request->search;
-            $query->where(function($q) use ($search) {
+        if ($request->filled('product_search')) {
+            $search = $request->product_search;
+            $productQuery->where(function($q) use ($search) {
                 $q->where('name', 'like', "%{$search}%")
                   ->orWhere('barcode', 'like', "%{$search}%")
                   ->orWhere('spec', 'like', "%{$search}%");
@@ -33,29 +37,66 @@ class ProductController extends Controller
 
         // 分類篩選
         if ($request->filled('category_id')) {
-            $query->where('category_id', $request->category_id);
+            $productQuery->where('category_id', $request->category_id);
         }
 
-        $per_page = $request->input('per_page', 10);
-        
-        $companyId = $user->company_id;
         if ($user->isSystemAdmin()) {
-            if ($request->filled('company_id')) {
-                $companyId = $request->company_id;
-                $query->where('company_id', $companyId);
+            if ($request->filled('product_company_id')) {
+                $productQuery->where('company_id', $request->product_company_id);
             }
         }
 
-        $products = $query->latest()->paginate($per_page)->withQueryString();
-        $categories = ProductCategory::with('translations')->get();
+        $products = $productQuery->latest()->paginate($per_page, ['*'], 'product_page')->withQueryString();
+
+        // Categories Query
+        $categoryQuery = ProductCategory::with(['translations', 'company']);
+        
+        if ($user->isSystemAdmin() && $request->filled('category_company_id')) {
+            $categoryQuery->where('company_id', $request->category_company_id);
+        }
+
+        if ($request->filled('category_search')) {
+            $search = $request->category_search;
+            $categoryQuery->where(function($q) use ($search) {
+                $q->where('name', 'like', "%{$search}%");
+            });
+        }
+
+        $categories = $categoryQuery->latest()->paginate($per_page, ['*'], 'category_page')->withQueryString();
         $companies = $user->isSystemAdmin() ? Company::all() : collect();
         
-        // 系統管理員在過濾特定公司時，應顯示該公司的功能開關 (如物料代碼、點數規則)
-        $selectedCompany = $companyId ? Company::find($companyId) : $user->company;
+        // Settings for Modal (use current user company or fallback)
+        $selectedCompanyId = $user->isSystemAdmin() 
+            ? ($request->input('product_company_id') ?: $request->input('category_company_id')) 
+            : $user->company_id;
+        $selectedCompany = $selectedCompanyId ? Company::find($selectedCompanyId) : $user->company;
         $companySettings = $selectedCompany ? ($selectedCompany->settings ?? []) : [];
         
         $routeName = 'admin.data-config.products.index';
 
+        if ($request->ajax() || $request->wantsJson()) {
+            if ($tab === 'products') {
+                return response()->json([
+                    'success' => true,
+                    'html' => view('admin.products.partials.tab-products', [
+                        'products' => $products,
+                        'companySettings' => $companySettings,
+                        'companies' => $companies,
+                        'routeName' => $routeName
+                    ])->render()
+                ]);
+            } else {
+                return response()->json([
+                    'success' => true,
+                    'html' => view('admin.products.partials.tab-categories', [
+                        'categories' => $categories,
+                        'companies' => $companies,
+                        'routeName' => $routeName
+                    ])->render()
+                ]);
+            }
+        }
+
         return view('admin.products.index', [
             'products' => $products,
             'categories' => $categories,
@@ -313,8 +354,23 @@ class ProductController extends Controller
             $product->save();
 
             $status = $product->is_active ? __('Enabled') : __('Disabled');
+            
+            if (request()->ajax()) {
+                return response()->json([
+                    'success' => true,
+                    'message' => __('Product status updated to :status', ['status' => $status]),
+                    'is_active' => $product->is_active
+                ]);
+            }
+
             return redirect()->back()->with('success', __('Product status updated to :status', ['status' => $status]));
         } catch (\Exception $e) {
+            if (request()->ajax()) {
+                return response()->json([
+                    'success' => false,
+                    'message' => $e->getMessage()
+                ], 500);
+            }
             return redirect()->back()->with('error', $e->getMessage());
         }
     }
@@ -337,8 +393,21 @@ class ProductController extends Controller
 
             $product->delete();
 
+            if (request()->ajax()) {
+                return response()->json([
+                    'success' => true,
+                    'message' => __('Product deleted successfully')
+                ]);
+            }
+
             return redirect()->back()->with('success', __('Product deleted successfully'));
         } catch (\Exception $e) {
+            if (request()->ajax()) {
+                return response()->json([
+                    'success' => false,
+                    'message' => $e->getMessage()
+                ], 500);
+            }
             return redirect()->back()->with('error', $e->getMessage());
         }
     }