feat: use upstream walker and elephant flakes

flake.nix

@@ -18,6 +18,12 @@
     #vicinae.url = "github:vicinaehq/vicinae";
     vicinae-extensions.url = "github:vicinaehq/extensions";
 
+    elephant.url = "github:abenz1267/elephant";
+    walker = {
+      url = "github:abenz1267/walker";
+      inputs.elephant.follows = "elephant";
+    };
+
     lux-pkgs.url = "git+ssh://gitea@orion/kiri/lux-pkgs";
   };