chore(test): Update flake.lock

Flake lock file updates:

• Updated input 'flake-parts':
    'github:hercules-ci/flake-parts/644e0fc' (2025-07-21)
  → 'github:hercules-ci/flake-parts/250481a' (2026-01-05)
• Updated input 'flake-parts/nixpkgs-lib':
    'github:nix-community/nixpkgs.lib/14a40a1' (2025-06-29)
  → 'github:nix-community/nixpkgs.lib/2075416' (2025-12-14)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/6027c30' (2025-07-25)
  → 'github:nixos/nixpkgs/3146c6a' (2026-01-10)
• Updated input 'process-compose-flake':
    'github:Platonic-Systems/process-compose-flake/91dcc48' (2025-06-08)
  → 'github:Platonic-Systems/process-compose-flake/99bea96' (2026-01-08)
• Updated input 'services-flake':
    'github:juspay/services-flake/7b29107' (2025-07-25)
  → 'github:juspay/services-flake/8b6244f' (2025-12-08)

Author: github-actions[bot]