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',