fix: resolve final workbench re-review findings

apps/web/src/features/workbench/channels/CustomLinkChannel.test.ts

@@ -0,0 +1,36 @@
+import '@testing-library/jest-dom/vitest';
+import { cleanup, fireEvent, render, screen, waitFor } from '@testing-library/svelte';
+import { afterEach, describe, expect, it } from 'vitest';
+import CustomLinkChannel from './CustomLinkChannel.svelte';
+
+const channel = {
+  id: 'project-custom-link',
+  projectID: 1,
+  type: 'custom_link' as const,
+  title: 'Roadmap Board',
+  icon: 'link',
+  url: 'https://example.com/roadmap',
+  sortOrder: 1,
+};
+const originalClipboard = Object.getOwnPropertyDescriptor(navigator, 'clipboard');
+
+afterEach(() => {
+  cleanup();
+  if (originalClipboard) {
+    Object.defineProperty(navigator, 'clipboard', originalClipboard);
+  } else {
+    Reflect.deleteProperty(navigator, 'clipboard');
+  }
+});
+
+describe('CustomLinkChannel', () => {
+  it('reports unavailable clipboard access without showing URL copied', async () => {
+    Reflect.deleteProperty(navigator, 'clipboard');
+    render(CustomLinkChannel, { props: { channel } });
+
+    await fireEvent.click(screen.getByRole('button', { name: 'Copy URL' }));
+
+    await waitFor(() => expect(screen.getByText('Copy unavailable in this browser.')).toBeInTheDocument());
+    expect(screen.queryByText('URL copied.')).not.toBeInTheDocument();
+  });
+});