Add a "Clear All" Feature

A "Clear All" button should let the user reset the form, removing all author entries at once.

Files to modify: popup.html, popup.js

How to do it:

1. Add a button to the popup:

   <button type="button" id="clearAllBtn">Clear All</button>
   

2. In popup.js:

   document.getElementById('clearAllBtn').addEventListener('click', clearAllForms);
   
   function clearAllForms() {
     const container = document.getElementById('authorsContainer');
     while (container.firstChild) {
       container.removeChild(container.firstChild);
     }
     addAuthorForm(); // Optionally, re-add a single blank form
   }