fix(editor): prevent Tab key propagation outside editor (#11531)

Closes: BS-2964

blocksuite/affine/blocks/root/src/common-specs/index.ts

@@ -42,6 +42,7 @@ import type { ExtensionType } from '@blocksuite/store';
 import { RootBlockAdapterExtensions } from '../adapters/extension';
 import { clipboardConfigs } from '../clipboard';
 import { builtinToolbarConfig } from '../configs/toolbar';
+import { fallbackKeymap } from '../keyboard/keymap';
 import {
   innerModalWidget,
   linkedDocWidget,
@@ -94,6 +95,7 @@ export const CommonSpecs: ExtensionType[] = [
   viewportOverlayWidget,
   scrollAnchoringWidget,
   toolbarWidget,
+  fallbackKeymap,
 
   ToolbarModuleExtension({
     id: BlockFlavourIdentifier(NoteBlockSchema.model.flavour),

blocksuite/affine/blocks/root/src/keyboard/keymap.ts

@@ -0,0 +1,16 @@
+import { KeymapExtension } from '@blocksuite/std';
+
+export const fallbackKeymap = KeymapExtension(() => {
+  return {
+    Tab: ctx => {
+      const event = ctx.get('defaultState').event;
+      event.stopPropagation();
+      event.preventDefault();
+    },
+    'Shift-Tab': ctx => {
+      const event = ctx.get('defaultState').event;
+      event.stopPropagation();
+      event.preventDefault();
+    },
+  };
+});