feat(player): 完善 H5 投注端与 API 演示数据

- 球赛/串关/优胜冠军、赛事详情、历史投注与个人资料编辑
- 固定顶栏、公告与底栏，仅内容区滚动
- 底部导航与站点 favicon 使用 logo，登录页精简
- API 种子、冠军盘与历史注单增强

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/src/shared/common/decorators.ts

@@ -32,10 +32,18 @@ export function generateBatchNo(prefix: string): string {
   return `${prefix}${ts}`;
 }
 
+function isDecimalLike(obj: object): obj is { toJSON: () => string } {
+  return (
+    typeof (obj as { toJSON?: unknown }).toJSON === 'function' &&
+    typeof (obj as { toFixed?: unknown }).toFixed === 'function'
+  );
+}
+
 export function serializeBigInt(obj: unknown): unknown {
   if (obj === null || obj === undefined) return obj;
   if (typeof obj === 'bigint') return obj.toString();
   if (obj instanceof Date) return obj.toISOString();
+  if (typeof obj === 'object' && isDecimalLike(obj)) return obj.toJSON();
   if (Array.isArray(obj)) return obj.map(serializeBigInt);
   if (typeof obj === 'object') {
     const result: Record<string, unknown> = {};