test(tui): wait for tab layout before scrolling

The transcript can render before asynchronous tab registration adds its layout row. Wait for the tab title as well as the final message so the one-line scroll assertion starts with a stable viewport.

packages/tui/test/app-lifecycle.test.tsx

@@ -922,8 +922,9 @@ test("error investigations repeatedly seed editable home drafts without creating
 })
 
 test("shows jump to latest after scrolling one line above the final message", async () => {
+  await using state = await tmpdir()
   const session = {
-    id: "dummy",
+    id: "ses_scroll",
     title: "Demo session",
     projectID: "project",
     location: { directory },
@@ -942,18 +943,20 @@ test("shows jump to latest after scrolling one line above the final message", as
   await using setup = await createAppFixture({
     width: 80,
     height: 20,
+    state: state.path,
     config: { animations: false, keybinds: { "session.line.up": "f6", "session.line.down": "f7" } },
-    args: { sessionID: "dummy" },
+    args: { sessionID: "ses_scroll" },
     fetch: (url) => {
       if (url.pathname === "/api/session") return json({ data: [session], cursor: {} })
-      if (url.pathname === "/api/session/dummy") return json({ data: session })
-      if (url.pathname === "/api/session/dummy/message") return json({ data: messages.toReversed(), cursor: {} })
-      if (url.pathname === "/api/session/dummy/inbox") return json({ data: [] })
-      if (url.pathname === "/api/session/dummy/permission") return json({ data: [] })
+      if (url.pathname === "/api/session/ses_scroll") return json({ data: session })
+      if (url.pathname === "/api/session/ses_scroll/message") return json({ data: messages.toReversed(), cursor: {} })
+      if (url.pathname === "/api/session/ses_scroll/inbox") return json({ data: [] })
+      if (url.pathname === "/api/session/ses_scroll/permission") return json({ data: [] })
     },
   })
 
-  await setup.waitForFrame((frame) => frame.includes("Final visible message"))
+  // Persisting the tab adds a layout row, so wait for it before measuring the transcript.
+  await setup.waitForFrame((frame) => frame.includes(session.title) && frame.includes("Final visible message"))
   const findScrollBox = (root: Renderable): ScrollBoxRenderable | undefined =>
     root instanceof ScrollBoxRenderable && root.getRenderable("message-7")
       ? root