Function render_public_sql_error 

pub fn render_public_sql_error(
    error: &WritePlaneError,
    transaction_state: Option<&str>,
) -> (u16, Value)

Render one one-shot public SQL error — the single classification-to-bytes truth every host shares (the replicator’s old master_sql_error match, arm for arm). A host classifies its own error type into WritePlaneError once, renders here, and wraps the (status, body) pair in its HTTP layer.