fix(editor): ci stability (#14704)

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

* **Chores**
* Improved Electron shutdown, diagnostics and tab teardown for more
reliable exits and forced cleanup on stubborn processes.
* **Tests**
* Added polling-based test helpers, stronger scroll/page readiness,
timeout-tolerant page selection, and async cleanup/worker teardown;
updated many tests to wait for UI/model updates and rendering frames.
* **Bug Fixes**
* Reduced flakiness by awaiting paragraph visibility, nested counts,
selection/navigation stability, tab counts, post-action renders, and
safer element interactions.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

tests/blocksuite/e2e/selection/block.spec.ts

@@ -143,6 +143,7 @@ test('select all should work for multiple notes in doc mode', async ({
 
 async function clickListIcon(page: Page, i = 0) {
   const locator = page.locator('.affine-list-block__prefix').nth(i);
+  await expect(locator).toBeVisible();
   await locator.click({
     force: true,
     position: {