获取赛事当前赔率。
查询模式:必需 fixtureId + 可选 bookmakers,可选过滤标志。
如果提供 since,返回 changedAt >= since 的赔率更新。
Your API key (query-based auth for v5).
Single fixture ID (e.g. id1400003160574219).
Comma/space-separated bookmaker slugs (default: all).
changedAt >= since (ms)
If set, filter by marketActive flag.
If set, filter by mainLine flag.
Returns FixtureOddsResponse (fixture meta + odds + bookmaker meta)