flake.lock: Update

Flake lock file updates:

• Updated input 'flake-parts':
    'github:hercules-ci/flake-parts/0678d89' (2026-05-05)
  → 'github:hercules-ci/flake-parts/f7c1a2d' (2026-05-13)
• Updated input 'git-hooks-nix':
    'github:cachix/git-hooks.nix/3cfd774' (2026-04-21)
  → 'github:cachix/git-hooks.nix/61ab0e8' (2026-05-11)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/549bd84' (2026-05-05)
  → 'github:nixos/nixpkgs/64c08a7' (2026-05-23)

Author: pinguibot