refactor：拆分 API 路由与请求校验，统一 final 类和代码风格

app/Models/SettlementBatch.php

@@ -4,11 +4,11 @@ namespace App\Models;
 
 use App\Lottery\SettlementBatchStatus;
 use Illuminate\Database\Eloquent\Model;
-use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\HasMany;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
 
 /** 单期单次结算批次 {@see settlement_batches} */
-class SettlementBatch extends Model
+final class SettlementBatch extends Model
 {
     protected $fillable = [
         'draw_id',