feat: add copy user ID menu item and rename copy link to copy direct link

Add 'Copy user ID' button to both desktop and mobile post menus, allowing users to copy the full author address. This provides a way to verify authenticity against the 8-char display ID. Also rename 'Copy link' to 'Copy direct link' for clarity. Update security comments to reflect the new approach and add translations for all 35 languages.

public/translations/zh/default.json

@@ -99,7 +99,6 @@
   "interface": "界面",
   "invalid_url": "无效的网址",
   "image_search": "图像搜索",
-  "copy_link": "复制链接",
   "hide_post": "隐藏帖子",
   "hide_thread": "隐藏主题",
   "unhide_post": "显示帖子",
@@ -276,5 +275,7 @@
   "type": "类型",
   "yes": "是",
   "no": "否",
-  "pending_mod_approval": "等待版主批准，用户不可见"
+  "pending_mod_approval": "等待版主批准，用户不可见",
+  "copy_user_id": "复制用户ID",
+  "copy_direct_link": "复制直接链接"
 }