feat(Sitemap, SEO): update sitemap generation and SEO configurations

- Enhanced update-sitemap.sh to generate a new sitemap structure with lastmod dates for additional URLs.
- Updated SEO configurations in server.js and seo.js to allow indexing for impressum and datenschutz pages.
- Introduced a list of noindex prefixes to manage SEO settings dynamically based on route paths.
- Added structured FAQ schema in index.html to improve search engine visibility and user engagement.

frontend/src/utils/seo.js

@@ -42,15 +42,38 @@ const ROUTE_SEO = {
   '/impressum': {
     title: 'Impressum | Trainingstagebuch',
     description: 'Impressum von Trainingstagebuch.',
-    robots: 'noindex,follow'
+    robots: 'index,follow'
   },
   '/datenschutz': {
     title: 'Datenschutzerklärung | Trainingstagebuch',
     description: 'Datenschutzerklärung von Trainingstagebuch.',
-    robots: 'noindex,follow'
+    robots: 'index,follow'
   }
 };
 
+const NOINDEX_PREFIXES = [
+  '/createclub',
+  '/showclub',
+  '/members',
+  '/diary',
+  '/pending-approvals',
+  '/schedule',
+  '/tournaments',
+  '/tournament-participations',
+  '/training-stats',
+  '/club-settings',
+  '/predefined-activities',
+  '/mytischtennis-account',
+  '/clicktt-account',
+  '/team-management',
+  '/permissions',
+  '/logs',
+  '/clicktt',
+  '/member-transfer-settings',
+  '/personal-settings',
+  '/orders'
+];
+
 function normalizePath(path = '/') {
   if (!path || path === '') return '/';
   if (path === '/') return '/';
@@ -63,13 +86,18 @@ export function getSeoConfigForPath(path) {
     .filter((routePath) => routePath !== '/' && normalizedPath.startsWith(routePath))
     .sort((a, b) => b.length - a.length)[0];
 
-  const routeSeo = (matchedPrefix && ROUTE_SEO[matchedPrefix]) || ROUTE_SEO[normalizedPath] || DEFAULT_SEO;
+  const routeSeo = (matchedPrefix && ROUTE_SEO[matchedPrefix]) || ROUTE_SEO[normalizedPath];
   const canonicalPath = normalizedPath === '/' ? '' : normalizedPath;
+  const shouldNoindex = !routeSeo && NOINDEX_PREFIXES.some((routePath) => normalizedPath.startsWith(routePath));
+  const finalSeo = routeSeo || {
+    ...DEFAULT_SEO,
+    robots: shouldNoindex ? 'noindex,follow' : DEFAULT_SEO.robots
+  };
 
   return {
-    title: routeSeo.title || DEFAULT_SEO.title,
-    description: routeSeo.description || DEFAULT_SEO.description,
-    robots: routeSeo.robots || DEFAULT_SEO.robots,
+    title: finalSeo.title || DEFAULT_SEO.title,
+    description: finalSeo.description || DEFAULT_SEO.description,
+    robots: finalSeo.robots || DEFAULT_SEO.robots,
     canonical: `${SITE_URL}${canonicalPath}`,
     url: `${SITE_URL}${canonicalPath}`,
     image: DEFAULT_IMAGE