You don't have to. NodeBB core makes sure all requests to those routes are from admins.
https://github.com/NodeBB/NodeBB/blob/master/src/routes/index.js#L125-L126
Yeah, like @frissdiegurke mentioned, timeago uses separate locale files to override the "templates", but there's no way to use multiple templates based on the situation (shorthand for some, full for others, etc) without fundamental changes to timeago itself.
Now that I think about it the widget might not be that difficult, it will just make a call to get the widget data and display it along with some code to let users vote and a link to the actual topic where the poll is located. So most of the code that is already in the plugin can be utilized for the widget. The widget would need a pollId setting in the ACP>widgets to let you display a poll.
