Add copy-link control for the encoded plan URL

ventures/dollhouse/index.html

@@ -30,8 +30,8 @@
           <div class="furniture-container" id="furniture-container"></div>
         </div>
         <div class="controls">
-          <button id="clear-btn" class="control-btn">Clear All</button>
-          <button id="download-btn" class="control-btn primary">Download Diorama</button>
+          <button id="clear-btn" class="control-btn" type="button">Clear All</button>
+          <button id="download-btn" class="control-btn primary" type="button">Download Diorama</button>
         </div>
       </div>
       <div class="preview-panel">
@@ -39,6 +39,7 @@
         <svg id="diorama-svg" xmlns="http://www.w3.org/2000/svg" width="100%" height="400"></svg>
         <div class="share-info">
           <p>Share this plan: <span id="share-url">Copy link from address bar</span></p>
+          <button id="copy-link-btn" class="control-btn" type="button">Copy link</button>
         </div>
       </div>
     </div>
@@ -117,4 +118,4 @@
 
   <script src="app.js"></script>
 </body>
-</html>
+</html>