feat(agent): add addressable queue operations

packages/host/apiproxy/src/api/events.schema.ts

@@ -10,7 +10,9 @@ import type { HostFrame, MuxFrame } from './events.ts'
 import type { Wire } from './rpc.schema.ts'
 import { rpcErrorSchema, rpcIdSchema } from './rpc.schema.ts'
 import { approvalRequestIdSchema } from './approvals.schema.ts'
-import { contentBlockSchema, sessionEventSchema, sessionIdSchema, toolEventViewSchema } from './sessions.schema.ts'
+import {
+  contentBlockSchema, inboxItemIdSchema, sessionEventSchema, sessionIdSchema, toolEventViewSchema,
+} from './sessions.schema.ts'
 import { workspaceIdSchema, workspaceViewSchema } from './workspace.schema.ts'
 
 /** Question shape validated strictly against core dsh-user-interaction. */
@@ -42,7 +44,15 @@ export const muxFrameSchema = z.discriminatedUnion('type', [
   // and must fail loud here, not reach the composer.
   z.object({ type: z.literal('question/requested'), sessionId: sessionIdSchema, questions: z.array(askUserQuestionItemSchema).min(1) }),
   z.object({ type: z.literal('question/resolved'), sessionId: sessionIdSchema, questionRpcId: rpcIdSchema, outcome: z.union([z.literal('answered'), z.literal('cancelled')]) }),
-  z.object({ type: z.literal('session/queued'), sessionId: sessionIdSchema, message: messageSchema, steering: z.boolean() }),
+  z.object({
+    type: z.literal('session/queue'),
+    sessionId: sessionIdSchema,
+    items: z.array(z.object({
+      id: inboxItemIdSchema,
+      message: messageSchema,
+      placement: z.union([z.literal('queued'), z.literal('steering')]),
+    })),
+  }),
   // value stays wide: it already passed its unit's own schema on the host,
   // and deep-validating here would import every domain's schema into the carrier.
   z.object({ type: z.literal('session/projection'), sessionId: sessionIdSchema, key: z.string().min(1), value: z.unknown(), seq: z.number().int().nonnegative() }),