[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/UtilityFeeAttachment.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace App\Modules\Finance\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Support\Facades\Storage;
+
+class UtilityFeeAttachment extends Model
+{
+    protected $fillable = [
+        'utility_fee_id',
+        'file_path',
+        'original_name',
+        'mime_type',
+        'size',
+    ];
+
+    protected $appends = ['url'];
+
+    /**
+     * 附件所属的公共事業費
+     */
+    public function utilityFee(): BelongsTo
+    {
+        return $this->belongsTo(UtilityFee::class);
+    }
+
+    /**
+     * 獲取附件的全路徑 URL
+     */
+    public function getUrlAttribute()
+    {
+        return tenant_asset($this->file_path);
+    }
+}