flake.lock: Update

Flake lock file updates:

• Updated input 'nixpkgs':
    'https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.2505.808864%2Brev-4e7667a90c167f7a81d906e5a75cba4ad8bee620/0198eaa3-105a-74fa-a9b2-0a930acea8de/source.tar.gz?narHash=sha256-TH1SfSP523QI7kcPiNtMAEuwZR3Jdz0MCDXPs7TS8uo%3D' (2025-08-26)
  → 'https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.2505.810395%2Brev-25e53aa156d47bad5082ff7618f5feb1f5e02d01/01998694-ad17-7fa8-8c3a-c8bc31d19657/source.tar.gz?narHash=sha256-F8WmEwFoHsnix7rt290R0rFXNJiMbClMZyIC/e%2BHYf0%3D' (2025-09-25)

Author: github-actions[bot]