fix(app): stale keyed show errors

packages/app/e2e/session/session-child-navigation.spec.ts

@@ -0,0 +1,37 @@
+import { seedSessionTask, withSession } from "../actions"
+import { test, expect } from "../fixtures"
+
+test("task tool child-session link does not trigger stale show errors", async ({ page, sdk, gotoSession }) => {
+  test.setTimeout(120_000)
+
+  const errs: string[] = []
+  const onError = (err: Error) => {
+    errs.push(err.message)
+  }
+  page.on("pageerror", onError)
+
+  await withSession(sdk, `e2e child nav ${Date.now()}`, async (session) => {
+    const child = await seedSessionTask(sdk, {
+      sessionID: session.id,
+      description: "Open child session",
+      prompt: "Search the repository for AssistantParts and then reply with exactly CHILD_OK.",
+    })
+
+    try {
+      await gotoSession(session.id)
+
+      const link = page
+        .locator("a.subagent-link")
+        .filter({ hasText: /open child session/i })
+        .first()
+      await expect(link).toBeVisible({ timeout: 30_000 })
+      await link.click()
+
+      await expect(page).toHaveURL(new RegExp(`/session/${child.sessionID}(?:[/?#]|$)`), { timeout: 30_000 })
+      await page.waitForTimeout(1000)
+      expect(errs).toEqual([])
+    } finally {
+      page.off("pageerror", onError)
+    }
+  })
+})