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.

Cargo.lock

@@ -279,7 +279,7 @@ checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
 [[package]]
 name = "cm-dashboard"
-version = "0.1.256"
+version = "0.1.257"
 dependencies = [
  "anyhow",
  "chrono",
@@ -301,7 +301,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.256"
+version = "0.1.257"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -325,7 +325,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.256"
+version = "0.1.257"
 dependencies = [
  "chrono",
  "serde",