flake.lock: Update

Flake lock file updates:

• Updated input 'hydra-staging':
    'github:NixOS/hydra/b256df11dcaef226ba4fb3f723edf6bdd13f9fc0' (2026-04-06)
  → 'github:NixOS/hydra/cd235f7de82e3b67e81b442b73f5f7a98791298c' (2026-04-08)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/e86e7cc7ac91192bf86f97d6d10b083ad6425289' (2026-04-05)
  → 'github:NixOS/nixpkgs/c3c25cbe51e14132b9f825e2a82e64c75ad204b0' (2026-04-09)
• Updated input 'nixpkgs-unstable':
    'github:NixOS/nixpkgs/5e11f7acce6c3469bef9df154d78534fa7ae8b6c' (2026-04-05)
  → 'github:NixOS/nixpkgs/0f7663154ff2fec150f9dbf5f81ec2785dc1e0db' (2026-04-09)
• Updated input 'sops-nix':
    'github:Mic92/sops-nix/a4ee2de76efb759fe8d4868c33dec9937897916f' (2026-04-05)
  → 'github:Mic92/sops-nix/d2e8438d5886e92bc5e7c40c035ab6cae0c41f76' (2026-04-08)
• Updated input 'srvos':
    'github:numtide/srvos/8677ae9b6569964e5a27e27abfb707a49a6b827f' (2026-04-02)
  → 'github:numtide/srvos/f56f1053ae9f878501d3a8ae1961c73d1d7abce3' (2026-04-09)
• Updated input 'treefmt-nix':
    'github:numtide/treefmt-nix/75925962939880974e3ab417879daffcba36c4a3' (2026-04-02)
  → 'github:numtide/treefmt-nix/790751ff7fd3801feeaf96d7dc416a8d581265ba' (2026-04-08)

Author: mweinelt