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/hotkey/multiline.spec.ts

@@ -107,12 +107,15 @@ test('should cut work multiple line', async ({ page }, testInfo) => {
   await dragBetweenIndices(page, [0, 1], [2, 2]);
   // cut
   await page.keyboard.press(`${SHORT_KEY}+x`);
+  await waitNextFrame(page, 200);
+  await assertRichTexts(page, ['19']);
   expect(await getPageSnapshot(page, true)).toMatchSnapshot(
     `${testInfo.title}_init.json`
   );
   await undoByKeyboard(page);
   const text = await readClipboardText(page);
   expect(text).toBe(`23 456 78`);
+  await assertRichTexts(page, ['123', '456', '789']);
   expect(await getPageSnapshot(page, true)).toMatchSnapshot(
     `${testInfo.title}_undo.json`
   );