feat(labor): 노임관리 API 구현

- Labor 모델 (BelongsToTenant, SoftDeletes)
- LaborController 7개 엔드포인트
- LaborService 비즈니스 로직
- FormRequest 4개 (Index/Store/Update/BulkDelete)
- 마이그레이션 및 라우트 등록

API: GET/POST /labor, GET/PUT/DELETE /labor/{id}, DELETE /labor/bulk, GET /labor/stats

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

app/Http/Requests/Labor/LaborBulkDeleteRequest.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace App\Http\Requests\Labor;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class LaborBulkDeleteRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'ids' => ['required', 'array', 'min:1'],
+            'ids.*' => ['required', 'integer', 'exists:labors,id'],
+        ];
+    }
+
+    public function messages(): array
+    {
+        return [
+            'ids.required' => __('validation.required', ['attribute' => '삭제 대상']),
+            'ids.array' => __('validation.array', ['attribute' => '삭제 대상']),
+            'ids.min' => __('validation.min.array', ['attribute' => '삭제 대상', 'min' => 1]),
+            'ids.*.exists' => __('validation.exists', ['attribute' => '노임 ID']),
+        ];
+    }
+}