Stop native chat jumping when Codex starts a foreground command (#26503)

* Keep foreground Codex commands out of the background strip

* Run the command-strip host regression in Node

* Exercise retained commands after their source turns end

src/main/codex/codex-persistent-command-retention.test.ts

@@ -110,11 +110,14 @@ describe('persistent command retention', () => {
         }).admission
       ).toEqual({ accepted: true })
     }
+    expect(tracker.tasks()).toEqual([])
     for (let thread = 0; thread < 7; thread += 1) {
+      const threadId = `thread-${thread}`
+      expect(tracker.threadCommands(threadId)).toHaveLength(64)
       expect(
         settleCodexJournalTurn({
           sessionId: 'session',
-          threadId: `thread-${thread}`,
+          threadId,
           turnId: 'turn',
           turnLifecycle: null,
           completedAt: 1,
@@ -125,6 +128,8 @@ describe('persistent command retention', () => {
           attributionFor: () => ({ turnScope: AGENT_JOURNAL_THREAD_SCOPE })
         })
       ).toEqual({ accepted: true })
+      expect(tracker.endTurn(threadId, 'turn')).toHaveLength(64)
+      expect(tracker.tasks()).toHaveLength((thread + 1) * 64)
     }
     expect(items.activeItems.size).toBe(448)
     expect(items.streams.persistentCount).toBe(448)