fix(codex): publish the turn tail for a subagent item the roster claims

Main's #19055 added a `subAgentActivity` arm to the provider activity table,
which is reached only through `publishActivity`. The roster's admission returned
above that call, so every `subAgentActivity` item bypassed it and a fan-out that
reports nothing else left the turn tail stuck on the previous frame's text.

`publishActivity` already no-ops on a refused admission and on a non-primary
thread, so routing the roster's admission through it is safe.

Also corrects a docstring the frames extraction copy-pasted onto
`settleOversizedNotification`.

src/main/codex/codex-structured-journal-translation-subagents.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import { agentJournalItemKey } from '../../shared/agent-session-journal-item-key'
+import type { AgentSessionTurnActivity } from '../../shared/agent-session-wire'
 import type {
   AgentJournalItemBody,
   AgentJournalItemIdentity
@@ -17,11 +18,13 @@ type Row = { key: string; body: AgentJournalItemBody }
 
 function harness() {
   const rows: Row[] = []
+  const activities: (AgentSessionTurnActivity | null)[] = []
   const sink: StructuredAgentSessionEventSink = {
     appendItem: (identity: AgentJournalItemIdentity, body) =>
       rows.push({ key: agentJournalItemKey(identity), body }),
     appendTombstone: () => {},
-    publish: () => {}
+    publish: () => {},
+    setActivity: (activity) => activities.push(activity)
   }
   const translator = createCodexJournalTranslator({
     sink,
@@ -31,7 +34,7 @@ function harness() {
       return () => {}
     }
   })
-  return { translator, rows }
+  return { translator, rows, activities }
 }
 
 function notification(method: string, params: unknown): CodexStructuredSessionEvent {
@@ -88,6 +91,22 @@ describe('codex journal translation — subagents', () => {
     expect(rows.filter((row) => row.key.startsWith('orca:codex-subagents'))).toHaveLength(1)
   })
 
+  // The roster claims the item, but claiming it must not take the turn tail with
+  // it: the activity table is reached only through the publish arm, so a bare
+  // return leaves the tail stuck on whatever the previous frame said.
+  it('still publishes the turn tail for an item the roster claims', () => {
+    const { translator, activities } = harness()
+
+    translator.handle(notification('turn/started', { turn: { id: TURN_ID } }))
+    activities.length = 0
+    deliverActivity(translator, subagentItem('started', 'child-1', '/root/read'))
+
+    expect(activities.at(-1)).toEqual({
+      turnId: TURN_ID,
+      text: 'Coordinating with another agent'
+    })
+  })
+
   it('consumes thread/tokenUsage/updated instead of swallowing it as chrome', () => {
     const { translator, rows } = harness()
 

src/main/codex/codex-structured-journal-translation.ts

@@ -191,7 +191,9 @@ export function createCodexJournalTranslator(
             })
           : null
         if (subagentAdmission) {
-          return subagentAdmission
+          // Not a bare return: the roster claiming the item must not skip the
+          // turn-tail arm, which is the only publisher of its activity copy.
+          return publishActivity(event, subagentAdmission)
         }
         const translated = items.handle(event)
         return publishActivity(
@@ -224,7 +226,8 @@ export function createCodexJournalTranslator(
     }
   }
 
-  /** Routes a `subAgentActivity` item to the roster; null when it is not one. */
+  /** Settles the item a notification the transport refused to carry left
+   *  mid-flight; null when the frame is not one. */
   function settleOversizedNotification(event: {
     sessionId: string
     threadId: string

src/main/native-chat/agent-session-wire/provider-frame-activity.test.ts

@@ -28,6 +28,16 @@ describe('provider frame activity', () => {
     expect(codexProviderFrameActivity('item/reasoning/summaryPartAdded', {})).toBeNull()
   })
 
+  it('names a fan-out from either Codex item type that reports one', () => {
+    for (const type of ['collabAgentToolCall', 'subAgentActivity']) {
+      expect(
+        codexProviderFrameActivity('item/started', {
+          item: { type, kind: 'started', agentThreadId: 'child-1', agentPath: '/root/read' }
+        })
+      ).toBe('Coordinating with another agent')
+    }
+  })
+
   it('uses Claude descriptions and safe semantic status without exposing tool labels', () => {
     expect(
       claudeProviderFrameActivity('message:system:task_started', {