feat: Phase 5 API 개발 완료 (사용자 초대, 알림설정, 계정관리, 거래명세서)

5.1 사용자 초대 기능:
- UserInvitation 마이그레이션, 모델, 서비스, 컨트롤러, Swagger
- 초대 발송/수락/취소/재발송 API

5.2 알림설정 확장:
- NotificationSetting 마이그레이션, 모델, 서비스, 컨트롤러, Swagger
- 채널별/유형별 알림 설정 관리

5.3 계정정보 수정 API:
- 회원탈퇴, 사용중지, 약관동의 관리
- AccountService, AccountController, Swagger

5.4 매출 거래명세서 API:
- 거래명세서 조회/발행/이메일발송
- SaleService 확장, Swagger 문서화

app/Http/Requests/UserInvitation/AcceptInvitationRequest.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace App\Http\Requests\UserInvitation;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class AcceptInvitationRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'name' => ['required', 'string', 'max:100'],
+            'password' => ['required', 'string', 'min:8', 'confirmed'],
+            'phone' => ['nullable', 'string', 'max:20'],
+        ];
+    }
+
+    public function messages(): array
+    {
+        return [
+            'name.required' => __('validation.required', ['attribute' => '이름']),
+            'password.required' => __('validation.required', ['attribute' => '비밀번호']),
+            'password.min' => __('validation.min.string', ['attribute' => '비밀번호', 'min' => 8]),
+            'password.confirmed' => __('validation.confirmed', ['attribute' => '비밀번호']),
+        ];
+    }
+}

app/Http/Requests/UserInvitation/InviteUserRequest.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace App\Http\Requests\UserInvitation;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class InviteUserRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'email' => ['required', 'email', 'max:255'],
+            'role_id' => ['nullable', 'integer', 'exists:roles,id'],
+            'message' => ['nullable', 'string', 'max:1000'],
+            'expires_days' => ['nullable', 'integer', 'min:1', 'max:30'],
+        ];
+    }
+
+    public function messages(): array
+    {
+        return [
+            'email.required' => __('validation.required', ['attribute' => '이메일']),
+            'email.email' => __('validation.email', ['attribute' => '이메일']),
+            'role_id.exists' => __('validation.exists', ['attribute' => '역할']),
+        ];
+    }
+}

app/Http/Requests/UserInvitation/ListInvitationRequest.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace App\Http\Requests\UserInvitation;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class ListInvitationRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'status' => ['nullable', 'string', 'in:pending,accepted,expired,cancelled'],
+            'search' => ['nullable', 'string', 'max:255'],
+            'sort_by' => ['nullable', 'string', 'in:created_at,expires_at,email'],
+            'sort_dir' => ['nullable', 'string', 'in:asc,desc'],
+            'per_page' => ['nullable', 'integer', 'min:1', 'max:100'],
+            'page' => ['nullable', 'integer', 'min:1'],
+        ];
+    }
+}