Add nixpkgs-services to flake.lock

Generated by `nix flake lock` — adds the nixpkgs-services input
(pinned to the same nixpkgs commit) for the service version overlay.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

nixos/ringtail/flake.lock

@@ -57,11 +57,28 @@
         "type": "github"
       }
     },
+    "nixpkgs-services": {
+      "locked": {
+        "lastModified": 1774388614,
+        "narHash": "sha256-tFwzTI0DdDzovdE9+Ras6CUss0yn8P9XV4Ja6RjA+nU=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "1073dad219cb244572b74da2b20c7fe39cb3fa9e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "1073dad219cb244572b74da2b20c7fe39cb3fa9e",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "disko": "disko",
         "home-manager": "home-manager",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "nixpkgs-services": "nixpkgs-services"
       }
     }
   },