feat(admin): 密码校验统一与后台 API/设置增强

- 管理端账号/代理/站点等密码最短长度统一为 6 位
- LotterySettings、审计日志展示、币种与报表接口等小修复
- 补充设置批量更新、注单、校验错误等相关测试

tests/Feature/AdminCurrencyApiTest.php

@@ -47,12 +47,12 @@ test('admin can create currency and normalize code', function (): void {
         ->postJson('/api/v1/admin/currencies', [
             'code' => 'eur',
             'name' => 'Euro',
-            'decimal_places' => 2,
             'is_enabled' => true,
             'is_bettable' => true,
         ])
         ->assertStatus(201)
         ->assertJsonPath('data.code', 'EUR')
+        ->assertJsonPath('data.decimal_places', 2)
         ->assertJsonPath('data.is_bettable', true);
 
     $this->assertDatabaseHas('currencies', [