feat: [stock] 재고 조정 API 추가

- GET /stocks/{id}/adjustments: 조정 이력 조회
- POST /stocks/{id}/adjustments: 조정 등록 (증감 수량 + 사유)
- StockTransaction에 adjustment reason 추가
- StoreStockAdjustmentRequest 검증 추가

app/Http/Controllers/Api/V1/StockController.php

@@ -4,6 +4,7 @@
 
 use App\Helpers\ApiResponse;
 use App\Http\Controllers\Controller;
+use App\Http\Requests\V1\Stock\StoreStockAdjustmentRequest;
 use App\Services\StockService;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
@@ -71,4 +72,32 @@ public function statsByItemType(): JsonResponse
 
         return ApiResponse::success($stats, __('message.fetched'));
     }
+
+    /**
+     * 재고 조정 이력 조회
+     */
+    public function adjustments(int $id): JsonResponse
+    {
+        try {
+            $adjustments = $this->service->adjustments($id);
+
+            return ApiResponse::success($adjustments, __('message.fetched'));
+        } catch (\Illuminate\Database\Eloquent\ModelNotFoundException $e) {
+            return ApiResponse::error(__('error.stock.not_found'), 404);
+        }
+    }
+
+    /**
+     * 재고 조정 등록
+     */
+    public function storeAdjustment(int $id, StoreStockAdjustmentRequest $request): JsonResponse
+    {
+        try {
+            $result = $this->service->createAdjustment($id, $request->validated());
+
+            return ApiResponse::success($result, __('message.created'));
+        } catch (\Illuminate\Database\Eloquent\ModelNotFoundException $e) {
+            return ApiResponse::error(__('error.stock.not_found'), 404);
+        }
+    }
 }