Fix login scan not restarting after logout

Move scan trigger from ViewModel init to LaunchedEffect in LoginScreen
so discovery runs each time the screen appears, not just on first creation.

app/src/main/java/com/omixlab/lckcontrol/app/ui/login/LoginScreen.kt

@@ -26,6 +26,11 @@ fun LoginScreen(
 ) {
     val uiState by viewModel.uiState.collectAsStateWithLifecycle()
 
+    // Start scanning each time the login screen appears
+    LaunchedEffect(Unit) {
+        viewModel.startScan()
+    }
+
     LaunchedEffect(uiState.loginSuccess) {
         if (uiState.loginSuccess) onLoginSuccess()
     }

app/src/main/java/com/omixlab/lckcontrol/app/ui/login/LoginViewModel.kt

@@ -57,10 +57,6 @@ class LoginViewModel @Inject constructor(
     private var scanJob: Job? = null
     private val lanTls by lazy { LanTlsFactory.create(context) }
 
-    init {
-        startScan()
-    }
-
     fun startScan() {
         scanJob?.cancel()
         _uiState.value = LoginUiState(phase = LoginPhase.SCANNING)