flake.lock: Update

Flake lock file updates:

• Updated input 'fenix':
    'github:nix-community/fenix/9f42df6d931262bc814ef681bcac6de779bebaeb?narHash=sha256-1Eb53rxrULE1%2BMTHhxJTPNMwKKD6bkROd98L8LgMtCM%3D' (2025-08-30)
  → 'github:nix-community/fenix/6ffcbf59c119b0c6384c7d98f18cea06a9af7e9c?narHash=sha256-J/rtMKVUAEqOFj0ogvcHKK8HbaKhw%2BtiNrDOpEM%2BZDY%3D' (2025-10-04)
• Updated input 'fenix/rust-analyzer-src':
    'github:rust-lang/rust-analyzer/67a58fdfebd72f4f9f737f2715ab21a260d88383?narHash=sha256-5U2p%2BgLtH17qtAZY1bdY0snoN/gRlQ8nH3LO%2BYw3hCk%3D' (2025-08-29)
  → 'github:rust-lang/rust-analyzer/472037b789cf593172d6adf3b8d9f7a429f6cd9b?narHash=sha256-7StxDed3v2fAWLkl%2BHse9FlpjT7Dk7Cn/4vxTFyEhIg%3D' (2025-10-01)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/a918bb3594dd243c2f8534b3be01b3cb4ed35fd1?narHash=sha256-ynQxPVN2FIPheUgTFhv01gYLbaiSOS7NgWJPm9LF9D0%3D' (2025-08-30)
  → 'github:NixOS/nixpkgs/27ac93958969b5f3dccd654b402599cf3de633ac?narHash=sha256-hhM8SUI6kQMei5TImFdNQy9EDT8g2hAD161DUtbfAy0%3D' (2025-10-04)

Author: github-actions[bot]