Bump flake.lock and Cargo.lock (#238)

* flake.lock: Update

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/c23193b943c6c689d70ee98ce3128239ed9e32d1?narHash=sha256-hLEO2TPj55KcUFUU1vgtHE9UEIOjRcH/4QbmfHNF820%3D' (2025-09-13)
  → 'github:NixOS/nixpkgs/2fbfb1d73d239d2402a8fe03963e37aab15abe8b?narHash=sha256-9VvC20PJPsleGMewwcWYKGzDIyjckEz8uWmT0vCDYK0%3D' (2025-12-11)

* cargo update

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Author: github-actions[bot]