feat: 增强开奖与设置控制器的币种支持功能

引入 CurrencyResolver，用于在 DrawCurrentController、DrawResultShowController 与 DrawResultsIndexController 中统一处理币种代码解析。
更新 DrawHallSnapshotBuilder 与 DrawResultViewService 的构建方法，新增币种代码参数支持，确保开奖相关功能中的币种处理一致性。
增强 SettingIndexController：新增允许访问的 KV 配置分组校验。
在 OddsStreamService、PlayConfigStreamService 与 RiskCapStreamService 中新增广播功能，用于在玩法目录变更时推送更新通知。
新增测试用例，验证风险限额发布的广播行为。

app/Http/Controllers/Api/V1/Setting/SettingIndexController.php

@@ -4,31 +4,44 @@ namespace App\Http\Controllers\Api\V1\Setting;
 
 use App\Http\Controllers\Controller;
 use App\Models\LotterySetting;
+use App\Lottery\ErrorCode;
 use App\Support\ApiResponse;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 
 /**
- * 玩家端/公开：读取 KV 配置（公开访问）
+ * 玩家端/公开：读取 KV 配置（公开访问；仅允许白名单分组）。
  */
 final class SettingIndexController extends Controller
 {
+    /** @var list<string> */
+    private const PUBLIC_GROUPS = [
+        'frontend',
+    ];
+
     public function __invoke(Request $request): JsonResponse
     {
         $group = $request->query('group');
-        
-        $query = LotterySetting::query()->orderBy('setting_key');
 
-        if (! empty($group)) {
-            $query->where('group_name', $group);
+        if (! is_string($group) || $group === '' || ! in_array($group, self::PUBLIC_GROUPS, true)) {
+            return ApiResponse::error(
+                'invalid_settings_group',
+                ErrorCode::ClientHttpError->value,
+                ['allowed_groups' => self::PUBLIC_GROUPS],
+                400,
+            );
         }
 
-        $items = $query->get()->map(fn (LotterySetting $s): array => [
-            'key' => $s->setting_key,
-            'value' => $s->value_json,
-            'group' => $s->group_name,
-            'description' => $s->description_zh,
-        ]);
+        $items = LotterySetting::query()
+            ->where('group_name', $group)
+            ->orderBy('setting_key')
+            ->get()
+            ->map(fn (LotterySetting $s): array => [
+                'key' => $s->setting_key,
+                'value' => $s->value_json,
+                'group' => $s->group_name,
+                'description' => $s->description_zh,
+            ]);
 
         return ApiResponse::success(['items' => $items]);
     }