feat(API): Inspection API 구현

- InspectionController 생성 (CRUD + stats + complete)
- InspectionService 생성 (비즈니스 로직)
- FormRequest 생성 (Store/Update/Complete)
- 라우트 등록 (7개 엔드포인트)
- i18n 메시지 추가 (message.php, error.php)

기존 inspections 테이블 및 Inspection 모델 활용

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

app/Http/Requests/Inspection/InspectionUpdateRequest.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Http\Requests\Inspection;
+
+use Illuminate\Foundation\Http\FormRequest;
+use Illuminate\Validation\Rule;
+
+class InspectionUpdateRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'items' => ['nullable', 'array'],
+            'items.*.id' => ['required_with:items', 'string'],
+            'items.*.result' => ['nullable', 'string', 'max:20'],
+            'items.*.measured_value' => ['nullable', 'numeric'],
+            'items.*.judgment' => ['nullable', Rule::in(['pass', 'fail'])],
+            'result' => ['nullable', Rule::in(['pass', 'fail'])],
+            'remarks' => ['nullable', 'string', 'max:1000'],
+            'opinion' => ['nullable', 'string', 'max:2000'],
+        ];
+    }
+}