feat: allow non-admin users to blocklist & search under specific conditions

- Added addedOn timestamp to qBittorrent torrent mapping
- Added canBlocklist helper function: true for admins, true for non-admins when (importIssues OR (torrent >1h old AND availability<100%))
- Added canBlocklist field to all download objects in /user-downloads and SSE /stream routes (8 blocks total)
- Frontend button now shows when (isAdmin OR download.canBlocklist) && download.arrQueueId

public/app.js

@@ -556,7 +556,7 @@ function createDownloadCard(download) {
     header.appendChild(issueBadge);
   }
 
-  if (isAdmin && download.arrQueueId) {
+  if ((isAdmin || download.canBlocklist) && download.arrQueueId) {
     const blBtn = document.createElement('button');
     blBtn.className = 'blocklist-search-btn';
     blBtn.textContent = '⛔ Blocklist & Search';