refactor(editor): new icon picker (#13658)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* In-tree icon picker for Callout blocks (emoji, app icons, images) with
popup UI and editor-wide extension/service.
* Callout toolbar adds background color presets, an icon-picker action,
and a destructive Delete action.

* **Refactor**
* Replaced legacy emoji workflow with icon-based rendering, updated
state, styling, and lifecycle for callouts.

* **Tests**
  * Updated callout E2E to reflect new default icon and picker behavior.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: L-Sun <zover.v@gmail.com>

tests/affine-local/e2e/blocksuite/callout/callout.spec.ts

@@ -24,9 +24,9 @@ test('add callout block using slash menu and change emoji', async ({
 }) => {
   await type(page, '/callout\naaaa\nbbbb');
   const callout = page.locator('affine-callout');
-  const emoji = page.locator('affine-callout .affine-callout-emoji');
+  const emoji = page.locator('affine-callout').getByTestId('callout-emoji');
   await expect(callout).toBeVisible();
-  await expect(emoji).toContainText('😀');
+  await expect(emoji).toContainText('💡');
 
   const paragraph = page.locator('affine-callout affine-paragraph');
   await expect(paragraph).toHaveCount(2);
@@ -35,18 +35,6 @@ test('add callout block using slash menu and change emoji', async ({
   await expect(vLine).toHaveCount(2);
   expect(await vLine.nth(0).innerText()).toBe('aaaa');
   expect(await vLine.nth(1).innerText()).toBe('bbbb');
-
-  await emoji.click();
-  const emojiMenu = page.locator('affine-emoji-menu');
-  await expect(emojiMenu).toBeVisible();
-  await page
-    .locator('div')
-    .filter({ hasText: /^😀😃😄😁😆😅🤣😂🙂$/ })
-    .getByLabel('😆')
-    .click();
-  await page.getByTestId('page-editor-blank').click();
-  await expect(emojiMenu).not.toBeVisible();
-  await expect(emoji).toContainText('😆');
 });
 
 test('press backspace after callout block', async ({ page }) => {