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/en/default.json

@@ -99,7 +99,6 @@
   "interface": "interface",
   "invalid_url": "Invalid URL",
   "image_search": "image search",
-  "copy_link": "Copy link",
   "hide_post": "Hide post",
   "hide_thread": "Hide thread",
   "unhide_post": "Unhide post",
@@ -276,5 +275,7 @@
   "type": "Type",
   "yes": "Yes",
   "no": "No",
-  "pending_mod_approval": "Pending mod approval, not visible to users"
+  "pending_mod_approval": "Pending mod approval, not visible to users",
+  "copy_user_id": "Copy user ID",
+  "copy_direct_link": "Copy direct link"
 }