fix(apiproxy): derive queued steering on the client, drop it from the wire

The session/queued frame no longer carries steering — AgentMessage no longer
has the field. The client derives it from the same ordered turn boundaries the
host saw (a frame arriving while a turn is open joined the steering FIFO).

packages/client/runtime/src/client/sessions/session.ts

@@ -105,6 +105,11 @@ export class Session implements ObservableSnapshot<ConversationSnapshot> {
   private dispatchesRev = 0
   private dispatchesCache: { rev: number; value: ReadonlyMap<string, readonly CodeSubCall[]> } | null = null
   private running = false
+  /** Whether a turn is open on the live stream — set on turn/start, cleared on
+   *  turn/end. A session/queued frame arriving while this is true joined the
+   *  steering FIFO; the host no longer stamps steering on the frame, so the
+   *  client derives it from the same ordered turn boundaries the host saw. */
+  private turnOpen = false
   /**
    * Sticky send marker, private input of the composerPhase derivation: set
    * synchronously before prompt()'s first await, never reset — the blank →
@@ -334,6 +339,12 @@ export class Session implements ObservableSnapshot<ConversationSnapshot> {
     switch (frame.type) {
       case 'session/event': {
         this.retireQueued(frame.event)
+        // Track turn-open state AFTER retirement (a message turn/start first
+        // claims its queued entry, then opens the turn), so a later queued
+        // frame is stamped steering iff a turn is open — the host no longer
+        // stamps it on the frame.
+        if (frame.event.type === 'turn/start') this.turnOpen = true
+        else if (frame.event.type === 'turn/end') this.turnOpen = false
         this.acceptLiveEvent(frame.event, frame.view)
         return
       }
@@ -343,7 +354,7 @@ export class Session implements ObservableSnapshot<ConversationSnapshot> {
         const key = 'rpcId' in frame.source ? String(frame.source.rpcId) : `f:${rpcId}`
         this.queued.push({
           row: { key, preview: queuePreviewOf(frame.content) },
-          steering: frame.steering,
+          steering: this.turnOpen,
           sourceJson: JSON.stringify(frame.source),
         })
         this.queueRev++

packages/client/runtime/tests/queue-store.spec.ts

@@ -17,10 +17,10 @@ const text = (t: string): ContentBlock[] => [{ type: 'text', text: t }]
 const rid = (id: string): RpcId => id as RpcId
 
 /** session/queued frame with the wire-sourced rpcId key (the host prompt path). */
-function queuedFrame(body: string, rpcId: string, steering = false): MuxFrame {
+function queuedFrame(body: string, rpcId: string): MuxFrame {
   return {
     type: 'session/queued', sessionId: SID, content: text(body),
-    source: { kind: 'user', rpcId: rid(rpcId) } as never, steering,
+    source: { kind: 'user', rpcId: rid(rpcId) } as never,
   }
 }
 
@@ -41,7 +41,7 @@ describe('queue intake', () => {
     session.handleMuxEnvelope(rid('env-2'), {
       type: 'session/queued', sessionId: SID,
       content: [{ type: 'text', text: 'hi' }, { type: 'image', data: 'x' } as never],
-      source: { kind: 'plugin', plugin: 'loop' }, steering: false,
+      source: { kind: 'plugin', plugin: 'loop' },
     })
     expect(session.getSnapshot().queue).toEqual([{ key: 'f:env-2', preview: 'hi [image]' }])
   })
@@ -85,22 +85,29 @@ describe('queue retirement (host queuedMirror rules)', () => {
 
   it('steering/message drains the source-matched steering row only', () => {
     const session = makeSession()
-    session.handleMuxEnvelope(rid('e1'), queuedFrame('普通', 'p-1'))
-    session.handleMuxEnvelope(rid('e2'), queuedFrame('插话', 'p-2', true))
+    session.handleMuxEnvelope(rid('e1'), queuedFrame('普通', 'p-1')) // idle → non-steering
+    // Injection-triggered turn/start opens the turn without claiming a row, so
+    // the next queued frame is derived steering (arrived mid-turn).
+    const injection = {
+      ...ev.turnStart(0, 0),
+      data: { turn: 0, trigger: { kind: 'injection', source: { kind: 'plugin', plugin: 'x' } } },
+    } as never
+    session.handleMuxEnvelope(rid('e2'), { type: 'session/event', sessionId: SID, event: injection })
+    session.handleMuxEnvelope(rid('e3'), queuedFrame('插话', 'p-2')) // turn open → steering
     // Loop-authored steering (different source) must not consume the user entry.
     const foreignSteering = {
       seq: 0, time: 1,
       type: 'steering/message', surfaceOp: 'append',
       data: { turn: 0, content: text('loop'), source: { kind: 'plugin', plugin: 'loop' } },
     } as never
-    session.handleMuxEnvelope(rid('e3'), { type: 'session/event', sessionId: SID, event: foreignSteering })
+    session.handleMuxEnvelope(rid('e4'), { type: 'session/event', sessionId: SID, event: foreignSteering })
     expect(session.getSnapshot().queue).toHaveLength(2)
     const matchedSteering = {
       seq: 1, time: 2,
       type: 'steering/message', surfaceOp: 'append',
       data: { turn: 0, content: text('插话'), source: { kind: 'user', rpcId: rid('p-2') } },
     } as never
-    session.handleMuxEnvelope(rid('e4'), { type: 'session/event', sessionId: SID, event: matchedSteering })
+    session.handleMuxEnvelope(rid('e5'), { type: 'session/event', sessionId: SID, event: matchedSteering })
     expect(session.getSnapshot().queue.map(r => r.key)).toEqual(['p-1'])
   })
 
@@ -108,7 +115,7 @@ describe('queue retirement (host queuedMirror rules)', () => {
     const session = makeSession()
     session.handleRunning(true)
     session.handleMuxEnvelope(rid('e1'), queuedFrame('一', 'p-1'))
-    session.handleMuxEnvelope(rid('e2'), queuedFrame('二', 'p-2', true))
+    session.handleMuxEnvelope(rid('e2'), queuedFrame('二', 'p-2'))
     session.handleRunning(false)
     expect(session.getSnapshot().queue).toEqual([])
   })

packages/client/ui-conversation/tests/input-machine.spec.ts

@@ -36,7 +36,7 @@ function effectAt<T extends InputEffect['type']>(
 ): Extract<InputEffect, { type: T }> {
   const e = effects[index]
   expect(e?.type).toBe(type)
-  return e
+  return e as Extract<InputEffect, { type: T }>
 }
 
 /** Drive plain → adjudicating and hand back the minted attempt. */

packages/client/ui-subagent/tests/browser-plugin.spec.ts

@@ -22,7 +22,7 @@ function summary(partial: Partial<SessionSummary> & { id: SessionId }): SessionS
     running: false,
     updatedAt: 0,
     ...partial,
-  }
+  } as SessionSummary
 }
 
 const sid = (id: string) => id as SessionId