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

server/utils/qbittorrent.js

@@ -204,6 +204,7 @@ function mapTorrentToDownload(torrent) {
     category: torrent.category,
     tags: torrent.tags,
     savePath: torrent.content_path || torrent.save_path || null,
+    addedOn: torrent.added_on || null,
     qbittorrent: true
   };
 }