chore: implementiere Zustandsprüfung für DiscoveryService und ConnectivityTracker, verbessere Plug-and-Play-Kompatibilität und optimiere LAN-Discovery

Signed-off-by: StefanMoCoAt <stefan.mo.co@gmail.com>

frontend/shells/meldestelle-desktop/src/jvmMain/kotlin/at/mocode/frontend/shell/desktop/screens/layout/DesktopMainLayout.kt

@@ -996,11 +996,18 @@ private fun DesktopFooterBar(
   val deviceName = settings.deviceName.ifBlank { "Unbekannt" }
 
   // Periodisches Update der LAN-Geräte (mDNS)
-  LaunchedEffect(Unit) {
-    discoveryService.startDiscovery()
-    while (true) {
-      discoveredServices.value = discoveryService.getDiscoveredServices()
-      delay(5000.milliseconds)
+  LaunchedEffect(settings.isConfigured, settings.deviceName) {
+    if (settings.isConfigured && settings.deviceName.isNotBlank()) {
+      discoveryService.startDiscovery()
+      connectivityTracker.startTracking()
+
+      while (true) {
+        discoveredServices.value = discoveryService.getDiscoveredServices()
+        delay(5000.milliseconds)
+      }
+    } else {
+      discoveryService.stopDiscovery()
+      connectivityTracker.stopTracking()
     }
   }