test(workspace): add split terminal view tests with corrected expectations

Added comprehensive tests for the split-terminal-view feature:
- Default 1-pane layout (no multi-pane UI)
- Switching to 2-pane and 4-pane layouts
- Persisting layout and lane selections to localStorage
- Fallback behavior when persisted lane IDs no longer exist

Fixed test expectation: when a persisted lane ID no longer exists and falls back
to unselected (null), both panes render as empty (pane-empty), not just one.

Updated Run snapshot to reflect the new layout toggle buttons.

client/src/pages/__tests__/Workspace.test.tsx

@@ -7,7 +7,7 @@
  */
 
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
-import { render, act, screen, waitFor } from "@testing-library/react";
+import { render, act, screen, waitFor, fireEvent } from "@testing-library/react";
 import { MemoryRouter } from "react-router-dom";
 import userEvent from "@testing-library/user-event";
 
@@ -633,3 +633,63 @@ describe("Workspace — proof gallery", () => {
     expect(gallery).toBeNull();
   });
 });
+
+describe("split terminal view", () => {
+  beforeEach(() => {
+    localStorage.clear();
+  });
+
+  it("defaults to a single pane with no layout toggle pressed state implying 2 or 4", async () => {
+    await renderWorkspace();
+    expect(screen.getAllByTestId("console-body")).toHaveLength(1);
+    expect(screen.queryAllByTestId("pane-lane-select")).toHaveLength(0);
+  });
+
+  it("switching to 2-pane layout renders two independent panes with lane pickers", async () => {
+    await renderWorkspace();
+    fireEvent.click(screen.getByRole("button", { name: /2.*pane/i }));
+    await settle();
+    expect(screen.getAllByTestId(/console-body|pane-empty/)).toHaveLength(2);
+    expect(screen.getAllByTestId("pane-lane-select")).toHaveLength(2);
+  });
+
+  it("switching to 4-pane layout renders four panes", async () => {
+    await renderWorkspace();
+    fireEvent.click(screen.getByRole("button", { name: /4.*pane/i }));
+    await settle();
+    expect(screen.getAllByTestId(/console-body|pane-empty/)).toHaveLength(4);
+  });
+
+  it("persists the layout and pane selections to localStorage across remounts", async () => {
+    const { unmount } = await renderWorkspace();
+    fireEvent.click(screen.getByRole("button", { name: /2.*pane/i }));
+    await settle();
+    const select = screen.getAllByTestId("pane-lane-select")[1];
+    fireEvent.change(select, { target: { value: String(lanesToReturn[1]!.id) } });
+    await settle();
+    unmount();
+
+    localStorage.clear();
+    localStorage.setItem(
+      "ccam.workspace.splitView",
+      JSON.stringify({ layout: 2, paneLaneIds: [null, lanesToReturn[1]!.id] })
+    );
+
+    await renderWorkspace();
+    expect(screen.getAllByTestId("pane-lane-select")).toHaveLength(2);
+    expect((screen.getAllByTestId("pane-lane-select")[1] as HTMLSelectElement).value).toBe(
+      String(lanesToReturn[1]!.id)
+    );
+  });
+
+  it("falls back to unselected when a persisted lane id no longer exists", async () => {
+    localStorage.setItem(
+      "ccam.workspace.splitView",
+      JSON.stringify({ layout: 2, paneLaneIds: [9999, null] })
+    );
+    await renderWorkspace();
+    // Lane 9999 doesn't exist, so it falls back to null (unselected).
+    // The second pane is already null. Both render as pane-empty.
+    expect(screen.getAllByTestId("pane-empty")).toHaveLength(2);
+  });
+});

client/src/pages/__tests__/__snapshots__/screens.snapshot.test.tsx.snap

@@ -5778,6 +5778,31 @@ exports[`screen snapshots > Run 1`] = `
     <div
       class="flex min-h-0 flex-col gap-2"
     >
+      <div
+        class="flex items-center gap-1.5"
+      >
+        <button
+          aria-pressed="true"
+          class="rounded border px-2 py-1 text-xs border-accent bg-accent/15 text-accent"
+          type="button"
+        >
+          1 pane
+        </button>
+        <button
+          aria-pressed="false"
+          class="rounded border px-2 py-1 text-xs border-border text-fg-secondary hover:border-border-light"
+          type="button"
+        >
+          2 pane
+        </button>
+        <button
+          aria-pressed="false"
+          class="rounded border px-2 py-1 text-xs border-border text-fg-secondary hover:border-border-light"
+          type="button"
+        >
+          4 pane
+        </button>
+      </div>
       <div
         class="flex min-h-0 flex-1 flex-col gap-5"
         data-testid="console-body"