redirect .well-known/security.txt requests

.htaccess

@@ -4,4 +4,7 @@ DirectoryIndex launch.html
 <IfModule mod_rewrite.c>
   RewriteEngine On
   RewriteRule ^(README\.md|LICENSE|AGENTS\.md)$ - [NC,R=404,L]
+
+  # security.txt: redirect to central security contact
+  RewriteRule ^\.well-known/security\.txt$ https://www.bnvb-ingenieure.de/.well-known/security.txt [NC,R=301,L]
 </IfModule>