Add torrent copy operation monitoring

Add real-time monitoring of torrent copy operations when completed
downloads are copied from SSD to HDD storage.

Changes:
- Add marker file tracking during rsync operations
- Monitor active copy operations via /tmp/torrent-copy-active
- Display copy status as sub-service under openvpn-vpn-download
- Show currently copying torrent name in dashboard

The copy status appears as an informational sub-service while rsync
is actively copying completed torrents to permanent storage, providing
visibility into potentially long-running file transfer operations.

agent/src/collectors/systemd.rs

@@ -178,6 +178,18 @@ impl SystemdCollector {
                                 service_type: "torrent_stats".to_string(),
                             });
                         }
+
+                        // Add active torrent copy status
+                        if let Some(torrent_name) = self.get_active_torrent_copy() {
+                            let metrics = Vec::new();
+
+                            sub_services.push(SubServiceData {
+                                name: format!("Copy: {}", torrent_name),
+                                service_status: Status::Info,
+                                metrics,
+                                service_type: "torrent_copy".to_string(),
+                            });
+                        }
                     }
 
                     if service_name == "nftables" && status_info.active_state == "active" {
@@ -1088,6 +1100,18 @@ impl SystemdCollector {
 
         Some((active_count, download_mbps, upload_mbps))
     }
+
+    /// Check if torrent copy script is actively running
+    /// Returns: Some(torrent_name) if copy is in progress, None otherwise
+    fn get_active_torrent_copy(&self) -> Option<String> {
+        let marker_path = "/tmp/torrent-copy-active";
+
+        // Check if marker file exists and read torrent name
+        std::fs::read_to_string(marker_path)
+            .ok()
+            .map(|content| content.trim().to_string())
+            .filter(|name| !name.is_empty())
+    }
 }
 
 #[async_trait]