metadata api compatibility issue

https://github.com/deepseek-ai/FlashMLA/blob/1408756a88e52a25196b759eaf8db89d2b51b5a1/flash_mla/flash_mla_interface.py#L9

Hi, your updated metadata api change the variable name from num_heads_per_head_k to num_q_token_per_head_k, which will lead to compatibility issue, could you change the var name back or define a new python api for get_mla_metadata?

Start at flash_mla/flash_mla_interface.py#L9 and inspect get_mla_metadata plus its existing Python callers. Done means the previous metadata variable name remains compatible, or a separate Python API is provided without breaking users of the current interface.

Written by the indexing model from the issue text.