fix: replace crypto.randomUUID with HTTP-compatible alternative

crypto.randomUUID() is only available in secure contexts (HTTPS).
Since the app runs over HTTP in development, this caused a blank page
crash on the external links admin page.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/core-service/src/core/settings/settings.controller.ts

@@ -10,6 +10,7 @@ import {
 import { ApiTags, ApiOperation } from '@nestjs/swagger';
 import { Roles } from '../../common/decorators/roles.decorator';
 import { RolesGuard } from '../../common/guards/roles.guard';
+import { randomUUID } from 'crypto';
 import { RedisService } from '../../redis/redis.service';
 
 /**
@@ -84,7 +85,7 @@ export class SettingsController {
 
     // Sortierung sicherstellen
     const sorted = body.links.map((link, index) => ({
-      id: link.id || crypto.randomUUID(),
+      id: link.id || randomUUID(),
       label: link.label.trim(),
       url: link.url.trim(),
       icon: link.icon || undefined,

packages/frontend/src/admin/AdminExternalLinksPage.tsx

@@ -2,6 +2,11 @@ import { useState, useEffect, useRef } from 'react';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import api from '../api/client';
 
+/** Einfache ID-Generierung (crypto.randomUUID ist nur ueber HTTPS verfuegbar) */
+function generateId(): string {
+  return Date.now().toString(36) + Math.random().toString(36).slice(2, 10);
+}
+
 interface ExternalLink {
   id: string;
   label: string;
@@ -300,7 +305,7 @@ export function AdminExternalLinksPage() {
     setLinks((prev) => [
       ...prev,
       {
-        id: crypto.randomUUID(),
+        id: generateId(),
         label: '',
         url: '',
         icon: undefined,