Function run_side_question 

async fn run_side_question(
    deps: AgentTurnDeps,
    mstore: Arc<Store>,
    filestore: Arc<FileStore>,
    broker: Arc<Broker>,
    boot_id: Arc<str>,
    source_block_id: String,
    question: String,
    context_snapshot: String,
    request_id: String,
)

Drive one /btw request end to end: spawn the throwaway turn, drain + translate + republish its output, then clean up.