Function should_retry_without_temperature 

pub fn should_retry_without_temperature(
    status_code: u16,
    body_text: &str,
) -> bool

Returns true if an OpenAI(-compatible) error response indicates the temperature parameter is unsupported and callers should retry without it.

This is intentionally tolerant:

• checks status_code == 400
• prefers structured JSON fields (error.param, error.code)
• falls back to substring matching on error.message