Function render_transcript 

pub fn render_transcript(
    messages: &[Arc<Value>],
    evicted: &[usize],
    window: u64,
    before_tokens: u64,
) -> String

Plain text of every evicted message, in order, for grep and ranged read. Thinking is omitted (private reasoning; signed blocks cannot be re-sent out of their turn anyway); images and documents are named only.