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  - Streamlined and updated end-to-end tests to match the new selection flow and UI changes, removing outdated or redundant test cases.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-local/e2e/change-page-mode.spec.ts

@@ -72,7 +72,7 @@ test('default to edgeless by editor header items', async ({ page }) => {
   await clickSideBarAllPageButton(page);
   await waitForAllPagesLoad(page);
   const docItem = page.locator(
-    `[data-testid="page-list-item"]:has-text("this is a new page")`
+    `[data-testid="doc-list-item"]:has-text("this is a new page")`
   );
   expect(docItem).not.toBeUndefined();
   await docItem.click();