Not magically. That part is, for now, in the scope of the IDE/editor plug-in. You can feed Tern a set of files to analyze, but Tern doesn't, for example, scrape HTML files to determine inclusions.

The one exception is requirejs-style dependencies. Those, if you give Tern some information on where to look, it will resolve and automatically include. I'll do something similar for node.js-style require calls in the future.