fix(docs): remove iShare mention (puro 独立运营定位)

- docs.sections.getKey.note 键从 zh/en 删除
- DocsView 对应 <p class="note"> 段删掉
- 全仓再次 grep 确认无其他 ishare/iShare 引用

frontend/src/views/docs/DocsView.vue

@@ -12,7 +12,6 @@
         <div class="callout">
           <a href="mailto:admin@puro.im">admin@puro.im</a>
         </div>
-        <p class="note">{{ $t('docs.sections.getKey.note') }}</p>
       </section>
 
       <section id="codex" class="docs-section">