Fix talkkonnect status detection using systemd service file

The status check was showing "Not installed" even after successful
installation because it relied on PATH and file checks that weren't
working reliably.

Changes:
- Check for /etc/systemd/system/talkkonnect.service first
- This is the most reliable indicator of installation
- Systemd service file is created during install and requires root
- Falls back to command/file checks if service file doesn't exist

This ensures status shows correctly immediately after installation.

setup_intercom.sh

@@ -69,7 +69,10 @@ check_talkkonnect_status() {
     local installed=false
     local running=false
 
-    if command -v talkkonnect &>/dev/null || [[ -f "/home/$KIOSK_USER/go/bin/talkkonnect" ]]; then
+    # Check if systemd service exists (most reliable indicator)
+    if [[ -f /etc/systemd/system/talkkonnect.service ]] || \
+       command -v talkkonnect &>/dev/null || \
+       [[ -f "/home/$KIOSK_USER/go/bin/talkkonnect" ]]; then
         installed=true
         if systemctl is-active --quiet talkkonnect; then
             running=true