flake-update: update all inputs (#279)

Flake lock file updates:

• Updated input 'home-manager':
    'github:nix-community/home-manager/58fd7ff' (2026-03-01)
  → 'github:nix-community/home-manager/ef12a9a' (2026-03-13)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/dd9b079' (2026-02-27)
  → 'github:nixos/nixpkgs/c06b4ae' (2026-03-13)

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Author: github-actions[bot]