fix(webui): restore session drag and review findings

webui/src/tests/thinking-reasoning-shell.test.tsx

@@ -0,0 +1,52 @@
+import { render, screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import { ThinkingReasoningShell } from "@/components/thread/activity/ThinkingReasoningShell";
+
+function renderShell(expanded: boolean) {
+  return render(
+    <ThinkingReasoningShell
+      active={false}
+      expanded={expanded}
+      label="Thought"
+      viewportRef={() => undefined}
+      contentRef={() => undefined}
+      fadeTop={false}
+      fadeBottom={false}
+      onToggle={vi.fn()}
+      onScroll={vi.fn()}
+    >
+      <button type="button">Hidden action</button>
+    </ThinkingReasoningShell>,
+  );
+}
+
+describe("ThinkingReasoningShell", () => {
+  it("makes collapsed descendants inert as well as visually hidden", () => {
+    const { rerender } = renderShell(false);
+    const disclosure = screen.getByRole("button", { name: "Thought" });
+    const collapsible = disclosure.nextElementSibling;
+
+    expect(collapsible).toHaveAttribute("inert");
+    expect(collapsible).toHaveAttribute("aria-hidden", "true");
+
+    rerender(
+      <ThinkingReasoningShell
+        active={false}
+        expanded
+        label="Thought"
+        viewportRef={() => undefined}
+        contentRef={() => undefined}
+        fadeTop={false}
+        fadeBottom={false}
+        onToggle={vi.fn()}
+        onScroll={vi.fn()}
+      >
+        <button type="button">Hidden action</button>
+      </ThinkingReasoningShell>,
+    );
+
+    expect(disclosure.nextElementSibling).not.toHaveAttribute("inert");
+    expect(disclosure.nextElementSibling).toHaveAttribute("aria-hidden", "false");
+  });
+});