upgrade to nixos 25.11

- thefuck has been removed, use pay-repects instead
- 'glxinfo' has been renamed to/replaced by 'mesa-demos'
- options have been moved out of the 'xserver' namespace
- use default mesa drivers, remove amdvlk
- systemd global config has been moved and is not string-based anymore
- git settings have been moved to sub-attrset
- ssh default options generate a warning now but are not needed -> disable
- unpin nixpkgs version for servicepoint flakes

homeConfigurations/vinzenz/ssh.nix

@@ -1,6 +1,7 @@
 {
   config.programs.ssh = {
     enable = true;
+    enableDefaultConfig = false;
     matchBlocks = {
       "vpn2" = {
         host = "vpn2 hetzner-vpn2";