nix: pin flake input to nixos-25.11 and track flake.lock

.gitignore

@@ -24,10 +24,9 @@ package-manager-*
 .DS_Store
 Thumbs.db
 
-# Nix Cache to speed up tests
+# Nix cache to speed up tests
 .nix/
 .nix-dev-installed
-flake.lock
 
 # Ignore logs
 *.log

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1771714954,
+        "narHash": "sha256-nhZJPnBavtu40/L2aqpljrfUNb2rxmWTmSjK2c9UKds=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "afbbf774e2087c3d734266c22f96fca2e78d3620",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-25.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -6,7 +6,7 @@
   };
 
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
   };
 
   outputs = { self, nixpkgs }: