flake.lock: Update

Flake lock file updates:

• Updated input 'nixos-stable':
    'git+https://github.com/NixOS/nixpkgs?ref=nixos-25.05&rev=70c74b02eac46f4e4aa071e45a6189ce0f6d9265&shallow=1' (2025-06-06)
  → 'git+https://github.com/NixOS/nixpkgs?ref=nixos-25.05&rev=36ab78dab7da2e4e27911007033713bab534187b&shallow=1' (2025-06-17)
• Updated input 'nixos-unstable':
    'git+https://github.com/NixOS/nixpkgs?ref=nixpkgs-unstable&rev=08fcb0dcb59df0344652b38ea6326a2d8271baff&shallow=1' (2025-06-08)
  → 'git+https://github.com/NixOS/nixpkgs?ref=nixpkgs-unstable&rev=5395fb3ab3f97b9b7abca147249fa2e8ed27b192&shallow=1' (2025-06-18)

Author: github-actions[bot]