Steering a live gateway-owned run had no process-local agent in SESSION_AGENT_CACHE,
so it errored with "No agent cached" and dropped the typed text. Now detects the live
gateway ACTIVE_RUNS stream and queues the steer as the next turn (model/provider/profile
snapshotted first), updates the queue badge, clears the draft, shows a toast — without
cancelling the stream. Gateway sibling of the shipped #5597 fallback.
Codex SAFE + Fable SHIP-UX; byte-identical to PR head; 66 steer/busy-input tests pass;
Nathan visual-approved (desktop + mobile screenshots).
Co-authored-by: t <a@b>
Co-authored-by: rodboev <rodboev@users.noreply.github.com>
