[FEAT] 實作公共事業費附件上傳管理與更新 UI 協作規範防呆機制

app/Modules/Finance/Models/UtilityFee.php

@@ -7,9 +7,16 @@ use Illuminate\Database\Eloquent\Model;
 
 class UtilityFee extends Model
 {
-    /** @use HasFactory<\Database\Factories\UtilityFeeFactory> */
     use HasFactory;
 
+    /**
+     * 此公共事業費的附件
+     */
+    public function attachments()
+    {
+        return $this->hasMany(UtilityFeeAttachment::class);
+    }
+
     // 狀態常數
     const STATUS_PENDING = 'pending';
     const STATUS_PAID = 'paid';