feat: H-1 입고 관리 API 구현

- ReceivingController: CRUD 및 목록 조회 API
- ReceivingService: 입고 비즈니스 로직
- Receiving 모델: 다중 테넌트 지원
- FormRequest 검증 클래스
- Swagger 문서화
- receivings 테이블 마이그레이션

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/Http/Requests/V1/Receiving/ProcessReceivingRequest.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace App\Http\Requests\V1\Receiving;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class ProcessReceivingRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'receiving_qty' => ['required', 'numeric', 'min:0'],
+            'receiving_date' => ['nullable', 'date'],
+            'lot_no' => ['nullable', 'string', 'max:50'],
+            'supplier_lot' => ['nullable', 'string', 'max:50'],
+            'receiving_location' => ['required', 'string', 'max:100'],
+            'receiving_manager' => ['nullable', 'string', 'max:50'],
+            'remark' => ['nullable', 'string', 'max:1000'],
+        ];
+    }
+
+    public function messages(): array
+    {
+        return [
+            'receiving_qty.required' => __('validation.required', ['attribute' => '입고수량']),
+            'receiving_qty.numeric' => __('validation.numeric', ['attribute' => '입고수량']),
+            'receiving_qty.min' => __('validation.min.numeric', ['attribute' => '입고수량', 'min' => 0]),
+            'receiving_location.required' => __('validation.required', ['attribute' => '입고위치']),
+        ];
+    }
+}