telegram: bound photo download to 60s

HttpClient::request_timeout only covers send_request, not body collect,
so a stuck download would otherwise stall the entire long-poll loop
indefinitely. tokio::time::timeout at the call site keeps the failure
contained — a slow/dead download surfaces as the same [image: download
failed: ...] marker as any other error.

60s is generous for the 1-5MB photos Kent typically sends; Telegram's
bot getFile cap is 20MB, which would still complete on most connections.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

channels/telegram/src/main.rs

@@ -221,7 +221,15 @@ async fn get_updates(
                     error!("telegram photo: missing file_id in update {update_id}");
                     (caption, None)
                 } else {
-                    match download_telegram_file(client, token, file_id).await {
+                    // Bound the download — HttpClient::request_timeout only covers
+                    // send_request, not body collect, so an indefinitely-slow body
+                    // would otherwise stall every subsequent poll.
+                    let dl = tokio::time::timeout(
+                        std::time::Duration::from_secs(60),
+                        download_telegram_file(client, token, file_id),
+                    ).await
+                        .unwrap_or_else(|_| Err("download timed out after 60s".into()));
+                    match dl {
                         Ok(path) => (caption, Some(path)),
                         Err(e) => {
                             error!("telegram photo download failed (file_id={file_id}): {e}");