Remove Auftrag Ausliefern/Retoure stubs and sort Kundengruppen by sort field.

Placeholder sub-pages are dropped from routing and nav until delivery/return flows exist; the new-customer group dropdown now matches the API sort order.

src/pages/auftrag/ausliefern.jsx

@@ -1,14 +0,0 @@
-import { PureComponent } from 'react';
-import Typography from '@mui/material/Typography';
-
-class AuftragAusliefernPage extends PureComponent {
-  render() {
-    return (
-      <Typography color="text.secondary">
-        Ausliefern — Inhalt folgt.
-      </Typography>
-    );
-  }
-}
-
-export default AuftragAusliefernPage;

src/pages/auftrag/retoure.jsx

@@ -1,14 +0,0 @@
-import { PureComponent } from 'react';
-import Typography from '@mui/material/Typography';
-
-class AuftragRetourePage extends PureComponent {
-  render() {
-    return (
-      <Typography color="text.secondary">
-        Retoure — Inhalt folgt.
-      </Typography>
-    );
-  }
-}
-
-export default AuftragRetourePage;

src/pages/kunde/neu.jsx

@@ -15,9 +15,13 @@ import { backendErrorFrom } from '../../utils/backendError';
 import { notifyError } from '../../utils/notify';
 
 function sortGroups(groups) {
-  return [...groups].sort((a, b) =>
-    String(a.name).localeCompare(String(b.name), 'de'),
-  );
+  return [...groups].sort((a, b) => {
+    const bySort = a.sort - b.sort;
+    if (bySort !== 0) return bySort;
+    const byName = String(a.name).localeCompare(String(b.name), 'de');
+    if (byName !== 0) return byName;
+    return a.id - b.id;
+  });
 }
 
 class KundeNeuPage extends PureComponent {