fix(API): Controller 타입 및 코드 정리

- FcmController, EstimateController, ItemsController 개선
- LoanController, PositionController 수정
- ReceivablesController, SalaryController 수정
- StructureReviewController 수정

Co-Authored-By: Claude <noreply@anthropic.com>

app/Http/Controllers/Api/V1/Construction/StructureReviewController.php

@@ -86,4 +86,4 @@ public function stats(Request $request)
             return $this->service->stats($request->all());
         }, __('message.structure_review.fetched'));
     }
-}
+}