fix(syncthing): Persist Syncthing config (and thus ID)

modules/nixos/syncthing.nix

@@ -26,6 +26,10 @@ in {
       "nginx"
     ];
 
+    sydnix.impermanence.directories = [
+      "/var/lib/syncthing"
+    ];
+
     sydnix.deertopia.nginx.vhosts."syncthing".vhost = {
       forceSSL = true;
       enableACME = true;