Suppress noisy job control messages and ignore empty menu input

- Add disown after vpnui & to suppress "killed" messages
- Ignore empty/whitespace input in menu loop
- Remove "Invalid choice" error (just ignore silently)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/rego-tunnel/shared/cisco-vpn

@@ -620,6 +620,7 @@ start_watchdog() {
                 export GDK_BACKEND=x11
                 export WEBKIT_DISABLE_DMABUF_RENDERER=1
                 /opt/cisco/secureclient/bin/vpnui &
+                disown
                 sleep 3
 
                 # Run auto-login
@@ -682,6 +683,7 @@ start_anyconnect() {
     export WEBKIT_DISABLE_DMABUF_RENDERER=1
     /opt/cisco/secureclient/bin/vpnui &
     VPNUI_PID=$!
+    disown $VPNUI_PID
     log DEBUG "vpnui started with PID $VPNUI_PID"
 
     if [ "$do_auto_login" = "true" ]; then
@@ -859,6 +861,9 @@ while true; do
     read -r choice
     echo ""
 
+    # Ignore empty/whitespace input
+    [[ -z "${choice// }" ]] && continue
+
     case $choice in
         1) if [ "$SKIP_AUTO_LOGIN" = "true" ]; then
                 start_anyconnect "false"
@@ -876,6 +881,6 @@ while true; do
         9) show_hosts ;;
         e|E) edit_hosts ;;
         q|Q) log INFO "Goodbye!"; exit 0 ;;
-        *) log ERROR "Invalid choice" ;;
+        *) ;; # Ignore invalid input silently
     esac
 done