flake.lock: Update

Flake lock file updates:

• Updated input 'flake-parts':
    'github:hercules-ci/flake-parts/3107b77' (2026-04-01)
  → 'github:hercules-ci/flake-parts/5250617' (2026-05-01)
• Updated input 'flake-parts/nixpkgs-lib':
    'github:nix-community/nixpkgs.lib/333c4e0' (2026-03-29)
  → 'github:nix-community/nixpkgs.lib/f590132' (2026-04-26)
• Updated input 'git-hooks-nix':
    'github:cachix/git-hooks.nix/580633f' (2026-04-07)
  → 'github:cachix/git-hooks.nix/3cfd774' (2026-04-21)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/4c1018d' (2026-04-09)
  → 'github:nixos/nixpkgs/15f4ee4' (2026-04-30)

Author: pinguibot