Function spawn_container_logs_fetch 

pub fn spawn_container_logs_fetch<F>(
    ctx: OwnedSshContext,
    runtime: ContainerRuntime,
    container_id: String,
    container_name: String,
    tail: usize,
    send: F,
)
where
    F: FnOnce(String, String, String, Result<Vec<String>, String>) + Send + 'static,

Spawn a background thread to run container logs. Same shape as spawn_container_inspect_listing. In demo mode the SSH call is short-circuited with a deterministic synthetic log stream so the logs viewer (and its / search) is exercisable without a remote.