use crateAgent;
use crateMessage;
use crateBoxFuture;
/// Single-agent response primitive.
///
/// Extreme minimalism principle: exactly one method.
/// The kernel provides no convergence logic, no memory injection, no streaming —
/// all policy decisions belong to the caller.
///
/// `BoxFuture` is used instead of `async_trait` to keep the kernel dependency-free
/// (no `async_trait` macro dep).