refactor(website): 域名/邮箱/渠道收口到 src/config/site.ts 单一真相源

新增 SITE 配置(url/email/telegram/line/store),Footer、Pricing、astro.config
(canonical 域名)均改为引用它;改联系方式/域名只动一处。
astro.config.mjs 直接 import 该 TS(Astro 配置加载支持)。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/website/src/components/Footer.astro

@@ -1,6 +1,7 @@
 ---
 import Brand from './Brand.astro';
 import type { T } from '../i18n/strings';
+import { SITE } from '../config/site';
 
 interface Props { t: T }
 const { t } = Astro.props;
@@ -34,10 +35,10 @@ const { t } = Astro.props;
       <div>
         <h4>{t('ft.contact')}</h4>
         <ul>
-          <li><a class="mono">shop.pangolin.vpn</a></li>
-          <li><a class="mono" href="https://t.me/pangolin_app" target="_blank" rel="noopener">Telegram @pangolin_app</a></li>
-          <li><a class="mono">LINE @pangolinvpn</a></li>
-          <li><a class="mono" href="mailto:pangolin@yanmeiai.com">pangolin@yanmeiai.com</a></li>
+          <li><a class="mono">{SITE.store.label}</a></li>
+          <li><a class="mono" href={SITE.telegram.url} target="_blank" rel="noopener">Telegram {SITE.telegram.handle}</a></li>
+          <li><a class="mono">LINE {SITE.line.handle}</a></li>
+          <li><a class="mono" href={`mailto:${SITE.email}`}>{SITE.email}</a></li>
         </ul>
       </div>
     </div>