feat: Phase 8.3 회사 추가 API 구현

- 사업자등록번호 유효성 검사 API (바로빌 연동)
- 회사 추가 신청/승인/반려 워크플로우
- 신청 승인 시 테넌트 자동 생성 및 사용자 연결
- 관리자용 신청 목록/상세 조회
- 사용자용 내 신청 목록 조회
- Swagger 문서 및 i18n 메시지 추가

app/Http/Requests/V1/Company/CheckBusinessNumberRequest.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Http\Requests\V1\Company;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class CheckBusinessNumberRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'business_number' => 'required|string|min:10|max:13',
+        ];
+    }
+
+    public function messages(): array
+    {
+        return [
+            'business_number.required' => __('validation.required', ['attribute' => '사업자등록번호']),
+            'business_number.min' => __('validation.min.string', ['attribute' => '사업자등록번호', 'min' => 10]),
+        ];
+    }
+}

app/Http/Requests/V1/Company/CompanyRequestActionRequest.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace App\Http\Requests\V1\Company;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class CompanyRequestActionRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'reason' => 'nullable|string|max:500',
+        ];
+    }
+}

app/Http/Requests/V1/Company/CompanyRequestIndexRequest.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace App\Http\Requests\V1\Company;
+
+use App\Models\CompanyRequest;
+use Illuminate\Foundation\Http\FormRequest;
+use Illuminate\Validation\Rule;
+
+class CompanyRequestIndexRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'status' => ['nullable', Rule::in(CompanyRequest::STATUSES)],
+            'search' => 'nullable|string|max:100',
+            'start_date' => 'nullable|date',
+            'end_date' => 'nullable|date|after_or_equal:start_date',
+            'sort_by' => ['nullable', Rule::in(['created_at', 'company_name', 'status', 'processed_at'])],
+            'sort_dir' => ['nullable', Rule::in(['asc', 'desc'])],
+            'per_page' => 'nullable|integer|min:1|max:100',
+            'page' => 'nullable|integer|min:1',
+        ];
+    }
+}

app/Http/Requests/V1/Company/CompanyRequestStoreRequest.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace App\Http\Requests\V1\Company;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class CompanyRequestStoreRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'business_number' => 'required|string|min:10|max:13',
+            'company_name' => 'required|string|max:200',
+            'ceo_name' => 'nullable|string|max:50',
+            'address' => 'nullable|string|max:300',
+            'phone' => 'nullable|string|max:30',
+            'email' => 'nullable|email|max:100',
+            'message' => 'nullable|string|max:1000',
+        ];
+    }
+
+    public function messages(): array
+    {
+        return [
+            'business_number.required' => __('validation.required', ['attribute' => '사업자등록번호']),
+            'company_name.required' => __('validation.required', ['attribute' => '회사명']),
+        ];
+    }
+}