Add JavaScript for page version selector
Add and load the JavaScript that provides the interactive behavior for the page version selector.
The JavaScript should implement the following behaviors:
- Toggle the version menu when the user clicks the current version number
- Add the is-active class to the selector when active
- Close the version menu when the user clicks anywhere outside the menu
- Does not fail if the version menu is missing
The JavaScript file should be named 03-page-versions.js so it's loaded after the navigation script.