test(core): destroy editors in IndexingPlugin.test afterEach

The tests created BlockNoteEditor instances via createEditor() but never
destroyed them. prosemirror-view's DOMObserver keeps a setTimeout alive
waiting to flush pending mutations; when vitest tears down jsdom between
test files the timer fires against a torn-down document and throws
`ReferenceError: document is not defined`. Vitest catches it as an
unhandled error and fails the whole run even when all 16 assertions pass.

Local runs usually hit the lucky teardown ordering and pass; CI surfaces
the race intermittently. Tracking created editors and calling
_tiptapEditor.destroy() in afterEach ensures the DOMObserver timers are
canceled before jsdom goes away.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: nperez0111

packages/core/src/blocks/ListItem/NumberedListItem/IndexingPlugin.test.ts

@@ -1,5 +1,5 @@
 import { Selection } from "prosemirror-state";
-import { describe, expect, it } from "vitest";
+import { afterEach, describe, expect, it } from "vitest";
 
 import { BlockNoteEditor } from "../../../editor/BlockNoteEditor.js";
 
@@ -9,9 +9,22 @@ import { BlockNoteEditor } from "../../../editor/BlockNoteEditor.js";
 
 const PLUGIN_KEY = "numbered-list-indexing-decorations$";
 
+// Track editors created in each test so we can destroy them in afterEach —
+// otherwise prosemirror-view's DOMObserver leaves a setTimeout alive that
+// fires after vitest tears down jsdom, throwing
+// `ReferenceError: document is not defined` and failing the run.
+const activeEditors: BlockNoteEditor<any, any, any>[] = [];
+
+afterEach(() => {
+  while (activeEditors.length) {
+    activeEditors.pop()!._tiptapEditor.destroy();
+  }
+});
+
 function createEditor() {
   const editor = BlockNoteEditor.create();
   editor.mount(document.createElement("div"));
+  activeEditors.push(editor);
   return editor;
 }