feat: make chat-style tasks the default experience (#11101)

ui/src/components/transcript/useLiveRunTranscripts.test.tsx

@@ -515,4 +515,112 @@ describe("useLiveRunTranscripts", () => {
     });
     container.remove();
   });
+
+  it("retains an accumulated buffer through a transient empty poll (PAP-462 B3)", async () => {
+    const ts = "2026-08-08T00:00:00.000Z";
+    const row = JSON.stringify({
+      ts,
+      stream: "stdout",
+      chunk: '{"type":"acpx.text_delta","text":"hello"}\n',
+      seq: 1,
+    });
+    // Serve the buffered chunk on the FIRST persisted-log read only; every later
+    // read (including after the run reappears) returns nothing new. So the chunk
+    // can only be present the second time if the buffer survived the gap.
+    logMock.mockResolvedValue({ runId: "run-1", store: "memory", logRef: "log-1", content: "", nextOffset: 100 });
+    logMock.mockResolvedValueOnce({ runId: "run-1", store: "memory", logRef: "log-1", content: `${row}\n`, nextOffset: 100 });
+
+    const captured: { value: ReturnType<typeof useLiveRunTranscripts> | null } = { value: null };
+    function Harness({ runs }: { runs: Array<{ id: string; status: string; adapterType: string }> }) {
+      captured.value = useLiveRunTranscripts({ companyId: "company-1", runs, enableRealtimeUpdates: false });
+      return null;
+    }
+
+    const container = document.createElement("div");
+    document.body.appendChild(container);
+    const root = createRoot(container);
+    const runList = [{ id: "run-1", status: "running", adapterType: "gemini_local" }];
+
+    await act(async () => {
+      root.render(<Harness runs={runList} />);
+      await Promise.resolve();
+    });
+    expect(captured.value?.transcriptByRun.get("run-1")).toHaveLength(1);
+
+    // Transient empty poll: run momentarily absent from the list.
+    await act(async () => {
+      root.render(<Harness runs={[]} />);
+      await Promise.resolve();
+    });
+
+    // Run reappears within the grace window — the buffer must survive rather than
+    // re-hydrate from a (now empty) truncated read.
+    await act(async () => {
+      root.render(<Harness runs={runList} />);
+      await Promise.resolve();
+    });
+    expect(captured.value?.transcriptByRun.get("run-1")).toHaveLength(1);
+
+    act(() => {
+      root.unmount();
+    });
+    container.remove();
+  });
+
+  it("prunes a buffer once a run stays absent past the grace window (PAP-462 B3)", async () => {
+    vi.useFakeTimers();
+    try {
+      const ts = "2026-08-08T00:00:00.000Z";
+      const row = JSON.stringify({
+        ts,
+        stream: "stdout",
+        chunk: '{"type":"acpx.text_delta","text":"hello"}\n',
+        seq: 1,
+      });
+      logMock.mockResolvedValue({ runId: "run-1", store: "memory", logRef: "log-1", content: "", nextOffset: 100 });
+      logMock.mockResolvedValueOnce({ runId: "run-1", store: "memory", logRef: "log-1", content: `${row}\n`, nextOffset: 100 });
+
+      const captured: { value: ReturnType<typeof useLiveRunTranscripts> | null } = { value: null };
+      function Harness({ runs }: { runs: Array<{ id: string; status: string; adapterType: string }> }) {
+        captured.value = useLiveRunTranscripts({ companyId: "company-1", runs, enableRealtimeUpdates: false });
+        return null;
+      }
+
+      const container = document.createElement("div");
+      document.body.appendChild(container);
+      const root = createRoot(container);
+      const runList = [{ id: "run-1", status: "running", adapterType: "gemini_local" }];
+
+      await act(async () => {
+        root.render(<Harness runs={runList} />);
+        await Promise.resolve();
+      });
+      expect(captured.value?.transcriptByRun.get("run-1")).toHaveLength(1);
+
+      await act(async () => {
+        root.render(<Harness runs={[]} />);
+        await Promise.resolve();
+      });
+
+      // Stay absent long enough for the grace window to lapse and the deferred
+      // prune to fire.
+      await act(async () => {
+        await vi.advanceTimersByTimeAsync(25_000);
+      });
+
+      // On reappear the buffer is gone, so the (now empty) read rebuilds nothing.
+      await act(async () => {
+        root.render(<Harness runs={runList} />);
+        await Promise.resolve();
+      });
+      expect(captured.value?.transcriptByRun.get("run-1") ?? []).toHaveLength(0);
+
+      act(() => {
+        root.unmount();
+      });
+      container.remove();
+    } finally {
+      vi.useRealTimers();
+    }
+  });
 });