flake.lock: Update

Flake lock file updates:

• Updated input 'nixpkgs':
    'https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.1.886100%2Brev-08dacfca559e1d7da38f3cf05f1f45ee9bfd213c/019a329e-32b1-7e68-9599-4784bdd5f623/source.tar.gz' (2025-10-28)
  → 'https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.1.921484%2Brev-fb7944c166a3b630f177938e478f0378e64ce108/019b84e0-82f8-7204-a1a2-bfd69a1af2b2/source.tar.gz' (2026-01-02)

flake.lock

@@ -2,12 +2,12 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1761672384,
-        "narHash": "sha256-o9KF3DJL7g7iYMZq9SWgfS1BFlNbsm6xplRjVlOCkXI=",
-        "rev": "08dacfca559e1d7da38f3cf05f1f45ee9bfd213c",
-        "revCount": 886100,
+        "lastModified": 1767379071,
+        "narHash": "sha256-EgE0pxsrW9jp9YFMkHL9JMXxcqi/OoumPJYwf+Okucw=",
+        "rev": "fb7944c166a3b630f177938e478f0378e64ce108",
+        "revCount": 921484,
         "type": "tarball",
-        "url": "https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.1.886100%2Brev-08dacfca559e1d7da38f3cf05f1f45ee9bfd213c/019a329e-32b1-7e68-9599-4784bdd5f623/source.tar.gz"
+        "url": "https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.1.921484%2Brev-fb7944c166a3b630f177938e478f0378e64ce108/019b84e0-82f8-7204-a1a2-bfd69a1af2b2/source.tar.gz"
       },
       "original": {
         "type": "tarball",