اضافه شدن قابلیت share و نگهداری بلندمدت

frontend/viewer.js

@@ -1,3 +1,4 @@
+import { mountShare, viewerURL } from './share.js?v=1';
 import { Camera } from './camera.js';
 const viewport = document.querySelector('#viewport');
 const state = document.querySelector('#state');
@@ -87,7 +88,9 @@ async function start() {
     camera.x = camera.width/2-center.x*camera.scale; camera.y = camera.height/2-center.y*camera.scale; paint();
   }).observe(viewport);
   // Enforce configured expiry even when a viewer remains open.
+  mountShare(document.querySelector('#viewer-share'),viewerURL(location.pathname,token));
   function expire() {
+    if (result.expires_at === -1) return;
     const remaining = result.expires_at*1000-Date.now();
     if (remaining <= 0) { viewport.replaceChildren(); state.textContent = 'This schematic link has expired'; }
     else setTimeout(expire,Math.min(2147483647,remaining));