Chore(startup): Propagate server ip:port to UI via system properties

ClientApp.start parses <ip>:<port>, sets `casono.server.host` / `casono.server.port` and forwards the original launch arg to the JavaFX launcher.
Casinomainui reads JavaFX launch args and exposes the same system properties.
CasinomainuiController reads those properties and constructs `ClientService(host, port)` (no hardcoded defaults)."

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ClientApp.java

@@ -36,6 +36,12 @@ public class ClientApp {
         int port = Integer.parseInt(parts[1]);
 
         LOGGER.info("You've selected the client. It will connect port {} at host {}", port, host);
-        Launcher.main(new String[] {});
+        // Expose the chosen host/port to the UI via system properties so controllers
+        // (which read System.getProperty("casono.server.host"/"casono.server.port"))
+        // can obtain the correct connection information.
+        System.setProperty("casono.server.host", host);
+        System.setProperty("casono.server.port", Integer.toString(port));
+        // Forward the original address argument to the launcher as well.
+        Launcher.main(new String[] { arg });
     }
 }

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/lobbyui/Casinomainui.java

@@ -30,12 +30,21 @@ public class Casinomainui extends Application {
      * @throws IOException If loading the FXML fails.
      */
     public void start(Stage stage) throws IOException {
-        FXMLLoader fxmlLoader =
-                new FXMLLoader(getClass().getResource("/ui-structure/Casinomainui.fxml"));
+        // If the launcher passed an address argument (ip:port), expose it as
+        // system properties so controllers can read it without embedding defaults.
+        var raw = getParameters().getRaw();
+        if (raw != null && raw.size() > 0) {
+            String arg = raw.get(0);
+            String[] parts = arg.split(":", 2);
+            if (parts.length == 2) {
+                System.setProperty("casono.server.host", parts[0]);
+                System.setProperty("casono.server.port", parts[1]);
+            }
+        }
+        FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("/ui-structure/Casinomainui.fxml"));
         Scene scene = new Scene(fxmlLoader.load(), SCENE_WIDTH, SCENE_HEIGHT);
         stage.setTitle("Casono");
-        javafx.scene.image.Image icon =
-                new javafx.scene.image.Image(
+        javafx.scene.image.Image icon = new javafx.scene.image.Image(
                 getClass().getResource("/images/logoinverted.png").toExternalForm());
         stage.getIcons().add(icon);
         stage.setScene(scene);

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/lobbyui/CasinomainuiController.java

@@ -11,8 +11,12 @@ import javafx.scene.layout.VBox;
 import javafx.scene.shape.Rectangle;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import ch.unibas.dmi.dbis.cs108.casono.client.network.ClientService;
 
-/** Controller for the Casono main UI lobby. Handles UI initialization and user actions. */
+/**
+ * Controller for the Casono main UI lobby. Handles UI initialization and user
+ * actions.
+ */
 public class CasinomainuiController {
     private static final Logger LOGGER = LogManager.getLogger(CasinomainuiController.class);
 
@@ -41,8 +45,10 @@ public class CasinomainuiController {
         logoView.setImage(new Image(getClass().getResource("/images/logo.png").toExternalForm()));
 
         translationManager = LobbyButtonTranslationManager.getInstance();
-        gridManager =
-                new LobbyButtonGridManager(new javafx.scene.layout.GridPane(), translationManager);
+        String host = System.getProperty("casono.server.host");
+        int port = Integer.parseInt(System.getProperty("casono.server.port"));
+        ClientService clientService = new ClientService(host, port);
+        gridManager = new LobbyButtonGridManager(new javafx.scene.layout.GridPane(), translationManager, clientService);
         casinoTable.getChildren().clear();
         casinoTable.getChildren().add(gridManager.getGridPane());
         gridManager.renderLobbyButtons();
@@ -62,13 +68,13 @@ public class CasinomainuiController {
             return;
         }
         int buttonId = nextButtonId++;
-        int lobbyId = gridManager.createLobby();
         try {
+            int lobbyId = gridManager.createLobby();
             translationManager.addLobbyButton(buttonId, lobbyId);
             LOGGER.info("ButtonID: {}, LobbyID: {}", buttonId, lobbyId);
             gridManager.renderLobbyButtons();
         } catch (Exception e) {
-            LOGGER.error("Error while adding lobby button: {}", e.getMessage());
+            LOGGER.error("Failed to create or add lobby: {}", e.getMessage());
         }
     }
 }