Function decode_single_select_accept 

pub fn decode_single_select_accept(
    content: &Value,
    choices: &[String],
) -> Result<String>

Decode the accepted content payload of an elicitation/create single-select response back into the original display text.

Expects content.choice to be a "choice-<idx>" string whose index is in bounds against choices. Returns the original text. Returns Err if the field is missing, malformed, or out of range — the same defense-in-depth posture the RFD recommends.