feat(core): enable new all docs by default (#12404)

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **Refactor**
  - Simplified the user interface by always displaying the new All Pages view, removing the feature flag and old page version.
  - Updated selection interactions to use shift+click on document items instead of checkboxes.
  - Centralized drag-and-drop functionality in document list items and simplified drag handle behavior.
  - Generalized new page button component to accept standard HTML attributes.
  - Changed test ID attributes on new page buttons and list headers to use standard `data-testid`.

- **Bug Fixes**
  - Added stable test identifiers to new page buttons, document list items, menu items, and operation buttons for improved test reliability.
  - Enabled external drag-and-drop support on the trash button.

- **Tests**
  - Streamlined and updated end-to-end tests to match the new selection flow and UI changes, removing outdated or redundant test cases.
  - Simplified utility functions and wait conditions in test helpers for better accuracy and maintainability.
  - Updated selectors in tests to reflect new document item identifiers and centralized page element retrieval using utility functions.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

tests/affine-desktop/e2e/tabs.spec.ts

@@ -9,6 +9,7 @@ import {
   clickNewPageButton,
   createLinkedPage,
   dragTo,
+  getPageByTitle,
 } from '@affine-test/kit/utils/page-logic';
 import { clickSideBarAllPageButton } from '@affine-test/kit/utils/sidebar';
 import { expect } from '@playwright/test';
@@ -21,11 +22,6 @@ test('create new tab', async ({ views }) => {
   // new tab title should be All docs
   await expectTabTitle(page, 1, 'All docs');
   await expectActiveTab(page, 1);
-  page = await views.getActive();
-  // page content should be at all docs page
-  await expect(page.getByTestId('virtualized-page-list')).toContainText(
-    'All docs'
-  );
 });
 
 test('can switch & close tab by clicking', async ({ page }) => {
@@ -115,7 +111,7 @@ test('drag a page from "All pages" list to tabs header', async ({ page }) => {
 
   await dragTo(
     page,
-    page.locator(`[data-testid="page-list-item"]:has-text("${title}")`),
+    getPageByTitle(page, title),
     page.getByTestId('add-tab-view-button')
   );