Function append_dialogue_edit 

pub fn append_dialogue_edit(
    parsed_path: &Path,
    seq: i64,
    speaker: &str,
    text: &str,
) -> Result<()>

Append one dialogue-line edit record: {ts, seq, fields: {speaker, text}}. Unlike the SFX journal, both fields are always set — a dialogue line has no “clear this override” state.