feat: 增强玩家 API，新增 locale 和时间字段，更新钱包 API 以支持可用余额计算，添加错误码与多语言支持

app/Models/TransferOrder.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+/** 主站 ↔ 彩票划转订单 {@see transfer_orders} */
+class TransferOrder extends Model
+{
+    protected $fillable = [
+        'transfer_no',
+        'player_id',
+        'direction',
+        'currency_code',
+        'amount',
+        'idempotent_key',
+        'status',
+        'external_request_payload',
+        'external_response_payload',
+        'external_ref_no',
+        'fail_reason',
+        'finished_at',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'amount' => 'integer',
+            'external_request_payload' => 'array',
+            'external_response_payload' => 'array',
+            'finished_at' => 'datetime',
+        ];
+    }
+
+    public function player(): BelongsTo
+    {
+        return $this->belongsTo(Player::class);
+    }
+}