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=fe83bbdde2ccdc2cb9573aa846abe8363f79a97a&shallow=1' (2025-09-04)
• 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=ca77296380960cd497a765102eeb1356eb80fed0&shallow=1' (2025-09-05)

Author: github-actions[bot]