refactor(core): add keyPress event to fix IME space detection (#11700)

### TL;DR
Refactor space-triggered AI Widget activation logic from `keydown` to `keypress` event listeners

### Background

The `keydown` event triggered by a space may originate from:
1. Normal space insertion
2. Space triggered by input method confirming candidate words

In scenarios like (2), some browsers (see [ISSUE](https://github.com/toeverything/AFFiNE/issues/11541)) and input method callbacks produce events identical to scenario (1),making it impossible to distinguish between the two.

To fix this, the space-activated AI listener uses the `keypress` event:
In scenario 2, `event.which !== 32` (may be `30430` or other values) can be used to differentiate from scenario 1.

> CLOSE BS-3081

blocksuite/framework/std/src/event/control/keyboard.ts

@@ -59,6 +59,21 @@ export class KeyboardControl {
 
   private composition = false;
 
+  private readonly _press = (event: KeyboardEvent) => {
+    if (!this._shouldTrigger(event)) {
+      return;
+    }
+    const keyboardEventState = new KeyboardEventState({
+      event,
+      composing: this.composition,
+    });
+
+    this._dispatcher.run(
+      'keyPress',
+      this._createContext(event, keyboardEventState)
+    );
+  };
+
   constructor(private readonly _dispatcher: UIEventDispatcher) {}
 
   private _createContext(event: Event, keyboardState: KeyboardEventState) {
@@ -105,6 +120,11 @@ export class KeyboardControl {
   listen() {
     this._dispatcher.disposables.addFromEvent(document, 'keydown', this._down);
     this._dispatcher.disposables.addFromEvent(document, 'keyup', this._up);
+    this._dispatcher.disposables.addFromEvent(
+      document,
+      'keypress',
+      this._press
+    );
     this._dispatcher.disposables.addFromEvent(
       document,
       'compositionstart',

blocksuite/framework/std/src/event/dispatcher.ts

@@ -46,6 +46,7 @@ const eventNames = [
 
   'keyDown',
   'keyUp',
+  'keyPress',
 
   'selectionChange',
   'compositionStart',

packages/frontend/core/src/blocksuite/ai/entries/space/setup-space.ts

@@ -5,20 +5,31 @@ import { AIProvider } from '../../provider';
 import type { AffineAIPanelWidget } from '../../widgets/ai-panel/ai-panel';
 
 export function setupSpaceAIEntry(panel: AffineAIPanelWidget) {
-  panel.handleEvent('keyDown', ctx => {
+  // Background: The keydown event triggered by a space may originate from:
+  // 1. Normal space insertion
+  // 2. Space triggered by input method confirming candidate words
+  // In scenarios like (2), some browsers (see [ISSUE](https://github.com/toeverything/AFFiNE/issues/11541))
+  // and input method callbacks produce events identical to scenario (1),
+  // making it impossible to distinguish between the two.
+  //
+  // To fix this, the space-activated AI listener uses the `keypress` event:
+  // In scenario 2, `event.which !== 32` (may be `30430` or other values) can be used to differentiate from scenario 1.
+  panel.handleEvent('keyPress', ctx => {
     const host = panel.host;
     const keyboardState = ctx.get('keyboardState');
+    const event = keyboardState.raw;
     if (
       AIProvider.actions.chat &&
-      keyboardState.raw.key === ' ' &&
+      event.key === ' ' &&
-      !keyboardState.raw.isComposing
+      event.which === 32 &&
+      !event.isComposing
     ) {
       const selection = host.selection.find(TextSelection);
       if (selection && selection.isCollapsed() && selection.from.index === 0) {
         const block = host.view.getBlock(selection.blockId);
         if (!block?.model?.text || block.model.text?.length > 0) return;
 
-        keyboardState.raw.preventDefault();
+        event.preventDefault();
         handleInlineAskAIAction(host);
       }
     }

tests/affine-cloud-copilot/e2e/basic/guidance.spec.ts

@@ -0,0 +1,18 @@
+import { expect } from '@playwright/test';
+
+import { test } from '../base/base-test';
+
+test.describe('AIBasic/Guidance', () => {
+  test.beforeEach(async ({ page, utils }) => {
+    await utils.testUtils.setupTestEnvironment(page);
+  });
+
+  test('should show AI panel when space is pressed on empty paragraph', async ({
+    page,
+    utils,
+  }) => {
+    await utils.editor.focusToEditor(page);
+    await page.keyboard.press('Space');
+    await expect(page.locator('affine-ai-panel-widget')).toBeVisible();
+  });
+});