chore(nix): Update dependencies.

Flake lock file updates:

• Updated input 'nix-darwin':
    'github:LnL7/nix-darwin/c48e963a5558eb1c3827d59d21c5193622a1477c?narHash=sha256-BHdc43Lkayd%2B72W/NXRKHzX5AZ%2B28F3xaUs3a88/Uew%3D' (2025-09-25)
  → 'github:LnL7/nix-darwin/9a9ab01072f78823ca627ae5e895e40d493c3ecf?narHash=sha256-IGwy02SH5K2hzIFrKMRsCmyvwOwWxrcquiv4DbKL1S4%3D' (2025-10-13)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/dc704e6102e76aad573f63b74c742cd96f8f1e6c?narHash=sha256-O7eHcgkQXJNygY6AypkF9tFhsoDQjpNEojw3eFs73Ow%3D' (2025-10-02)
  → 'github:NixOS/nixpkgs/832e3b6db48508ae436c2c7bfc0cf914eac6938e?narHash=sha256-uTpzDHRASEDeFUuToWSQ46Re8beXyG9dx4W36FQa0/c%3D' (2025-10-12)
• Updated input 'treefmt-nix':
    'github:numtide/treefmt-nix/5eda4ee8121f97b218f7cc73f5172098d458f1d1?narHash=sha256-ySNJ008muQAds2JemiyrWYbwbG%2BV7S5wg3ZVKGHSFu8%3D' (2025-09-24)
  → 'github:numtide/treefmt-nix/761ae7aff00907b607125b2f57338b74177697ed?narHash=sha256-gq9rdocpmRZCwLS5vsHozwB6b5nrOBDNc2kkEaTXHfg%3D' (2025-10-10)

Author: github-actions[bot]