feat: implement comments and activity panel in workspace

- Added CommentsPanel component for managing comments on documents.
- Integrated comment creation, deletion, and resolution functionalities.
- Implemented activity tracking for document interactions.
- Enhanced SketchPage with editing and saving capabilities.
- Introduced template management API endpoints for creating, sharing, and deleting templates.
- Added runtime validation report for frontend and backend.
- Created GettingStartedPanel for user onboarding with template options.
- Implemented Playwright E2E tests for accessibility and export functionality.

frontend/e2e/phase8-export.spec.ts

@@ -0,0 +1,10 @@
+import { test, expect } from '@playwright/test'
+import { login } from './helpers'
+
+test('page export control is available from a readable page', async ({ page }) => {
+  test.skip(!process.env.E2E_USERNAME || !process.env.E2E_PASSWORD, 'Set E2E_USERNAME and E2E_PASSWORD')
+  expect(await login(page)).toBeTruthy()
+  const exportButton = page.getByRole('button', { name: /export page/i }).first()
+  await expect(exportButton).toBeVisible()
+  await expect(exportButton).toHaveAttribute('title', /export html/i)
+})