feat: redesign PickupStationDialog with tabbed interface and white card layout

- Replace red border frame with transparent border and white card

- Add TabSheet with address, appointments, and cargo tabs

- Improve dialog layout with rounded corners and flex structure

src/main/java/de/assecutor/votianlt/pages/base/ui/component/PickupStationDialog.java

@@ -437,15 +437,44 @@ public class PickupStationDialog extends Dialog {
         formLayout.add(customerComboBox, company, salutation, firstName, lastName, phone, streetLayout, addressAddition,
                 zipCityLayout, saveAddress);
 
+        // TabSheet with address, appointments, and cargo tabs
+        TabSheet tabSheet = new TabSheet();
+        tabSheet.setWidthFull();
+        tabSheet.setSizeFull();
+
+        addressTabError = createTabErrorIndicator();
+        appointmentsTabError = createTabErrorIndicator();
+        cargoTabError = createTabErrorIndicator();
+
+        Tab addressTab = tabSheet.add(translationHelper.getTranslation("addjob.tab.addresses"), formLayout);
+        addressTab.add(addressTabError);
+        Tab appointmentsTab = tabSheet.add(translationHelper.getTranslation("addjob.tab.appointments"),
+                createAppointmentsTab(availableAppUsers));
+        appointmentsTab.add(appointmentsTabError);
+        Tab cargoTab = tabSheet.add(translationHelper.getTranslation("addjob.tab.cargo"), createCargoTab());
+        cargoTab.add(cargoTabError);
+
         // Red border frame filling the dialog
         Div redFrame = new Div();
-        redFrame.getStyle().set("border", "10px solid red");
+        redFrame.getStyle().set("border", "10px solid transparent");
         redFrame.getStyle().set("border-radius", "0");
         redFrame.getStyle().set("box-sizing", "border-box");
+        redFrame.getStyle().set("display", "flex");
+        redFrame.getStyle().set("flex-direction", "column");
+        redFrame.getStyle().set("flex", "1");
         redFrame.setSizeFull();
 
+        // White card with rounded corners inside the red frame
+        Div whiteCard = new Div();
+        whiteCard.getStyle().set("background", "white");
+        whiteCard.getStyle().set("border-radius", "24px");
+        whiteCard.getStyle().set("flex", "1");
+        whiteCard.getStyle().set("overflow", "auto");
+        whiteCard.setSizeFull();
+        whiteCard.add(tabSheet);
+
+        redFrame.add(whiteCard);
         add(redFrame);
-        redFrame.getStyle().set("flex", "1");
 
         // Footer buttons
         Button saveButton = new Button(translationHelper.getTranslation("dialog.confirm"), e -> {