fix(docs): render share previews without remote emoji assets

apps/pac-docs/app/og/docs/[...slug]/route.tsx

@@ -3,6 +3,7 @@ import { notFound } from 'next/navigation';
 import { ImageResponse } from 'next/og';
 import { generate as DefaultImage } from 'fumadocs-ui/og';
 import { appName } from '@/lib/shared';
+import { ogText } from '@/lib/og-text';
 import { readFileSync } from 'node:fs';
 import { join } from 'node:path';
 
@@ -18,7 +19,7 @@ export async function GET(_req: Request, { params }: RouteContext<'/og/docs/[...
 
   return new ImageResponse(
     <div style={{ display: 'flex', width: '100%', height: '100%', fontFamily: 'PAC Docs Sans' }}>
-      <DefaultImage title={page.data.title} description={page.data.description} site={appName} />
+      <DefaultImage title={ogText(page.data.title)} description={ogText(page.data.description)} site={ogText(appName)} />
     </div>,
     {
       width: 1200,

apps/pac-docs/lib/og-text.ts

+/** 分享预览用纯文本；Next/OG 会为 emoji 下载远程素材，正文保持原样。 */
+export function ogText(text: string | undefined): string {
+  return (text ?? '').replace(/[\p{Extended_Pictographic}\p{Emoji_Presentation}\u200D\uFE0E\uFE0F\u20E3]/gu, '');
+}