flake.lock: Update

Flake lock file updates:

• Updated input 'devenv':
    'github:cachix/devenv/1f6bf58a7c2667a87766cadd8ba49100920645ca?narHash=sha256-Ppw7srsW%2B%2B2pCYZfB2CXQAuMjHvlq20txrFobAr9dAo%3D' (2026-08-14)
  → 'github:cachix/devenv/5844e78c960ab73bb92e131bc2902b39b9ee52dd?narHash=sha256-gEOKc1EhkbrUj7JTjxwlNyh42vu89lpiyP33ubx/NCw%3D' (2026-08-21)
• Updated input 'devenv/nix':
    'github:cachix/nix/59407321a92f7d34d4a53e38959294007c0bc37a?narHash=sha256-WcqKvA7f7TGrlDVd69T1UXUqVXJ%2BwfoRbO%2Bmg5L7/Rc%3D' (2026-08-09)
  → 'github:cachix/nix/f521bcc0b07d80921104a973996823392d247f7a?narHash=sha256-Mdi8Ge6bMMLO901i2WCMOkiwNTYiKJivKN2kRfGxvXo%3D' (2026-08-17)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/02e08985a27c65ffd33d434eeb2e660a2e4dc84d?narHash=sha256-QvnceIGTBeDvDd9oCn%2BGvdsnkquliuwbVgpiRH68qaQ%3D' (2026-08-14)
  → 'github:NixOS/nixpkgs/5880666fd9eb563038431edb35c2d0aa595884e6?narHash=sha256-OURZPknrTjQrlNyxPdqzyqmU/81Wes1CUP/Ft1Rv/YI%3D' (2026-08-20)
• Updated input 'treefmt-nix':
    'github:numtide/treefmt-nix/ae7910970dddc408fe6ab1c8e4b277bb21d72dc0?narHash=sha256-NLSyTCW4K4ofhNBllt3omPasm6QpralXH1DBZOc91Dw%3D' (2026-08-05)
  → 'github:numtide/treefmt-nix/27b3b12a8e6375f28ebe122f07d230ca5459bbfa?narHash=sha256-WSFCsDSE5ffgD2MqzkM2CYjeFiKhRF/dJUN8uedb6YE%3D' (2026-08-16)

Author: github-actions[bot]