feat(chat): message queue + steering — mid-turn injection at tool-result boundaries

Consume the message-queue + steering handoff ([email protected], [email protected]).
Re-pinned file: deps + re-mirrored .dispatch/*.reference.md.

- fold steering AgentEvent into the transcript as a provisional user bubble
  (after the tool-result it followed; no de-dup — the queue surface carried it)
- add rendererId: "message-queue" custom renderer (pure parser + MessageQueueList)
  rendered as a compact panel above the Composer (hidden when queue is empty)
- add ChatStore.queueMessage / AppStore.queueMessage — sends chat.queue WS op
  (trim/validate non-empty; auto-starts a turn if idle)
- Composer switches to chat.queue while generating (button → Queue, placeholder
  → Steer the conversation...)
- exhaustiveness guards updated for steering + chat.queue
- carry-to-new-turn needs no special handling (normal new turn)

664 tests green.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/core/wire/conformance.ts b/src/core/wire/conformance.ts
index 13be78c..6e87e5c 100644
--- a/src/core/wire/conformance.ts
+++ b/src/core/wire/conformance.ts
@@ -34,6 +34,8 @@ export function assertAgentEventExhaustive(event: AgentEvent): string {
 			return "turn-sealed";
 		case "step-complete":
 			return "step-complete";
+		case "steering":
+			return "steering";
 		default:
 			return event satisfies never;
 	}
@@ -102,6 +104,8 @@ export function assertWsClientMessageExhaustive(msg: WsClientMessage): string {
 			return "chat.subscribe";
 		case "chat.unsubscribe":
 			return "chat.unsubscribe";
+		case "chat.queue":
+			return "chat.queue";
 		default:
 			return msg satisfies never;
 	}