PCMConfig类中缺少关键属性

根据文档https://docs.coze.cn/developer_guides/streaming_chat_event，data.output_audio.pcm_config中应包含sample_rate、frame_size_ms、 limit_configlimit_config.period、limit_config.max_frame_num等多个属性，但实际上只有sample_rat一个属性。请尽快补充。

Start by locating the PCMConfig class and compare its current properties with the pcm_config section of the linked streaming chat event documentation. Add the documented missing attributes, including frame_size_ms and the limit_config values, then run the relevant SDK tests or serialization checks to confirm the complete configuration is represented.

Written by the indexing model from the issue text.