adopted new syncthing flake

flake.nix

@@ -23,6 +23,10 @@
     };
 
     # common config for syncthing
+    nix-syncthing = {
+      url = "git+https://git.jan-leila.com/jan-leila/nix-syncthing?ref=main";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
 
     # disk configurations
     disko = {
@@ -73,6 +77,7 @@
     self,
     nixpkgs,
     sops-nix,
+    nix-syncthing,
     home-manager,
     impermanence,
     ...
@@ -84,6 +89,7 @@
     mkNixosSystem = util.mkNixosSystem;
     mkDarwinSystem = util.mkDarwinSystem;
     mkHome = util.mkHome;
+    syncthingConfiguration = util.syncthingConfiguration;
 
     installerSystems = {
       basic = mkNixosInstaller "basic" [];
@@ -153,5 +159,7 @@
     darwinConfigurations = darwinSystems;
 
     homeConfigurations = homeConfigurations;
+
+    syncthingConfiguration = syncthingConfiguration;
   };
 }