Strange Boolean Ternary

[ncfrey]

Feedback: use_flash_attn: bool | None = None is a tri-state Boolean.

• Replace the tri-state Boolean with a clearer alternative:
  • Either make it strictly a bool with a well-defined default (True or False),
  • Or use an Enum like FlashAttentionOption = Enum("FlashAttentionOption", ["AUTO", "ENABLED", "DISABLED"]).

[young-su-ko]

I'd love to give this a go over the weekend!

[young-su-ko]

Addressed in #179