feat: I-1 미지급비용 관리 API 개발

- ExpectedExpense 모델 및 마이그레이션 생성
- ExpectedExpenseService 구현 (CRUD, 일괄삭제, 지급일 변경, 요약)
- ExpectedExpenseController REST API 구현
- FormRequest 검증 클래스 3개 생성
- Swagger API 문서 작성
- 라우트 추가 (8개 엔드포인트)

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

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

app/Models/Tenants/ExpectedExpense.php

@@ -0,0 +1,134 @@
+<?php
+
+namespace App\Models\Tenants;
+
+use App\Traits\BelongsToTenant;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\SoftDeletes;
+
+class ExpectedExpense extends Model
+{
+    use BelongsToTenant, SoftDeletes;
+
+    protected $fillable = [
+        'tenant_id',
+        'expected_payment_date',
+        'settlement_date',
+        'transaction_type',
+        'amount',
+        'client_id',
+        'client_name',
+        'bank_account_id',
+        'account_code',
+        'payment_status',
+        'approval_status',
+        'description',
+        'created_by',
+        'updated_by',
+        'deleted_by',
+    ];
+
+    protected $casts = [
+        'expected_payment_date' => 'date',
+        'settlement_date' => 'date',
+        'amount' => 'decimal:2',
+        'client_id' => 'integer',
+        'bank_account_id' => 'integer',
+    ];
+
+    /**
+     * 거래유형 목록
+     */
+    public const TRANSACTION_TYPES = [
+        'purchase' => '매입',
+        'advance' => '선급금',
+        'suspense' => '가지급금',
+        'rent' => '임대료',
+        'salary' => '급여',
+        'insurance' => '보험료',
+        'tax' => '세금',
+        'utilities' => '공과금',
+        'other' => '기타',
+    ];
+
+    /**
+     * 지급상태 목록
+     */
+    public const PAYMENT_STATUSES = [
+        'pending' => '미지급',
+        'partial' => '부분지급',
+        'paid' => '지급완료',
+        'overdue' => '연체',
+    ];
+
+    /**
+     * 결재상태 목록
+     */
+    public const APPROVAL_STATUSES = [
+        'none' => '미신청',
+        'pending' => '결재대기',
+        'approved' => '결재완료',
+        'rejected' => '반려',
+    ];
+
+    /**
+     * 거래처 관계
+     */
+    public function client(): BelongsTo
+    {
+        return $this->belongsTo(\App\Models\Orders\Client::class);
+    }
+
+    /**
+     * 계좌 관계
+     */
+    public function bankAccount(): BelongsTo
+    {
+        return $this->belongsTo(BankAccount::class);
+    }
+
+    /**
+     * 생성자 관계
+     */
+    public function creator(): BelongsTo
+    {
+        return $this->belongsTo(\App\Models\Members\User::class, 'created_by');
+    }
+
+    /**
+     * 거래처명 조회 (회원/비회원 통합)
+     */
+    public function getDisplayClientNameAttribute(): string
+    {
+        if ($this->client) {
+            return $this->client->name;
+        }
+
+        return $this->client_name ?? '';
+    }
+
+    /**
+     * 거래유형 라벨
+     */
+    public function getTransactionTypeLabelAttribute(): string
+    {
+        return self::TRANSACTION_TYPES[$this->transaction_type] ?? $this->transaction_type;
+    }
+
+    /**
+     * 지급상태 라벨
+     */
+    public function getPaymentStatusLabelAttribute(): string
+    {
+        return self::PAYMENT_STATUSES[$this->payment_status] ?? $this->payment_status;
+    }
+
+    /**
+     * 결재상태 라벨
+     */
+    public function getApprovalStatusLabelAttribute(): string
+    {
+        return self::APPROVAL_STATUSES[$this->approval_status] ?? $this->approval_status;
+    }
+}