feat: 修正庫存與撥補單邏輯並整合文件

1. 修復倉庫統計數據加總與樣式。
2. 修正可用庫存計算邏輯（排除不可銷售倉庫）。
3. 撥補單商品列表加入批號與效期顯示。
4. 修正撥補單儲存邏輯以支援精確批號轉移。
5. 整合 FEATURES.md 至 README.md。

app/Modules/Inventory/Controllers/WarehouseController.php

@@ -24,13 +24,45 @@ class WarehouseController extends Controller
             });
         }
 
-        $warehouses = $query->withSum('inventories as total_quantity', 'quantity')
+        $warehouses = $query->withSum('inventories as book_stock', 'quantity') // 帳面庫存 = 所有庫存總和
+            ->withSum(['inventories as available_stock' => function ($query) {
+                // 可用庫存 = 庫存 > 0 且 品質正常 且 (未過期 或 無效期)
+                $query->where('quantity', '>', 0)
+                      ->where('quality_status', 'normal')
+                      ->where(function ($q) {
+                          $q->whereNull('expiry_date')
+                            ->orWhere('expiry_date', '>=', now());
+                      });
+            }], 'quantity')
             ->orderBy('created_at', 'desc')
             ->paginate(10)
             ->withQueryString();
 
+        // 修正各倉庫列表中的可用庫存計算：若倉庫不可銷售，則可用庫存為 0
+        $warehouses->getCollection()->transform(function ($w) {
+            if (!$w->is_sellable) {
+                $w->available_stock = 0;
+            }
+            return $w;
+        });
+
+        // 計算全域總計 (不分頁)
+        $totals = [
+            'available_stock' => \App\Modules\Inventory\Models\Inventory::where('quantity', '>', 0)
+                ->where('quality_status', 'normal')
+                ->whereHas('warehouse', function ($q) {
+                    $q->where('is_sellable', true);
+                })
+                ->where(function ($q) {
+                    $q->whereNull('expiry_date')
+                      ->orWhere('expiry_date', '>=', now());
+                })->sum('quantity'),
+            'book_stock' => \App\Modules\Inventory\Models\Inventory::sum('quantity'),
+        ];
+
         return Inertia::render('Warehouse/Index', [
             'warehouses' => $warehouses,
+            'totals' => $totals,
             'filters' => $request->only(['search']),
         ]);
     }
@@ -41,9 +73,10 @@ class WarehouseController extends Controller
             'name' => 'required|string|max:50',
             'address' => 'nullable|string|max:255',
             'description' => 'nullable|string',
+            'is_sellable' => 'nullable|boolean',
         ]);
 
-        // Auto-generate code
+        // 自動產生代碼
         $prefix = 'WH';
         $lastWarehouse = Warehouse::latest('id')->first();
         $nextId = $lastWarehouse ? $lastWarehouse->id + 1 : 1;
@@ -62,6 +95,7 @@ class WarehouseController extends Controller
             'name' => 'required|string|max:50',
             'address' => 'nullable|string|max:255',
             'description' => 'nullable|string',
+            'is_sellable' => 'nullable|boolean',
         ]);
 
         $warehouse->update($validated);