feat(rsync): print status message when transfer starts

rsync output is fully captured — nothing visible while it runs.
Adds a "Rsync running — this may take a while..." line before each
attempt so the Unraid log viewer shows transfer progress clearly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Rsync/rsync.sh

@@ -219,6 +219,7 @@ ATTEMPT=0
 
 for (( ATTEMPT=1; ATTEMPT<=RETRY_COUNT; ATTEMPT++ )); do
     log "$ICON_RETRY Attempt $ATTEMPT of $RETRY_COUNT..."
+    echo "$ICON_SYNC  Rsync running — this may take a while..."
 
     RSYNC_OUTPUT=$(rsync "${RSYNC_OPTS[@]}" \
         -e "ssh -i $SSH_KEY -T -o Compression=no -o IPQoS=throughput" \