feat: broadcast agent events over control channel

src/infra/agent-events.ts

@@ -0,0 +1,31 @@
+export type AgentEventPayload = {
+  runId: string;
+  seq: number;
+  stream: "job" | "tool" | string;
+  ts: number;
+  data: Record<string, unknown>;
+};
+
+let seq = 0;
+const listeners = new Set<(evt: AgentEventPayload) => void>();
+
+export function emitAgentEvent(event: Omit<AgentEventPayload, "seq" | "ts">) {
+  const enriched: AgentEventPayload = {
+    ...event,
+    seq: ++seq,
+    ts: Date.now(),
+  };
+  for (const listener of listeners) {
+    try {
+      listener(enriched);
+    } catch {
+      /* ignore */
+    }
+  }
+}
+
+export function onAgentEvent(listener: (evt: AgentEventPayload) => void) {
+  listeners.add(listener);
+  return () => listeners.delete(listener);
+}
+