build(nix): update dependencies

• Updated input 'fenix':
    'github:nix-community/fenix/69e40dd' (2025-11-19)
  → 'github:nix-community/fenix/d4e14d3' (2025-11-20)
• Updated input 'fenix/rust-analyzer-src':
    'github:rust-lang/rust-analyzer/2efc800' (2025-11-11)
  → 'github:rust-lang/rust-analyzer/636c3aa' (2025-11-19)
• Updated input 'nixify':
    'github:rvolosatovs/nixify/1a7dcf0' (2025-11-19)
  → 'github:rvolosatovs/nixify/4a726e8' (2025-11-20)
• Updated input 'nixify/advisory-db':
    'github:rustsec/advisory-db/01aa671' (2025-11-18)
  → 'github:rustsec/advisory-db/0c6f0bb' (2025-11-19)
• Updated input 'nixify/rust-overlay':
    'github:oxalica/rust-overlay/42ce16c' (2025-11-18)
  → 'github:oxalica/rust-overlay/a9c35d6' (2025-11-19)
• Updated input 'nixpkgs-unstable':
    'github:NixOS/nixpkgs/6f37468' (2025-11-18)
  → 'github:NixOS/nixpkgs/a8d610a' (2025-11-20)

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Author: github-actions[bot]