chore: update flake.lock

Flake lock file updates:

• Updated input 'crane':
    'github:ipetkov/crane/7cf72d9' (2026-04-10)
  → 'github:ipetkov/crane/dc7496d' (2026-04-19)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/54170c5' (2026-04-10)
  → 'github:NixOS/nixpkgs/c7f4703' (2026-04-17)
• Updated input 'pyproject-build-systems':
    'github:pyproject-nix/build-system-pkgs/b6e74f4' (2026-03-18)
  → 'github:pyproject-nix/build-system-pkgs/ffaa216' (2026-04-20)
• Updated input 'pyproject-nix':
    'github:pyproject-nix/pyproject.nix/fb6b728' (2026-04-06)
  → 'github:pyproject-nix/pyproject.nix/1b0021e' (2026-04-16)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/3c27f4c' (2026-04-13)
  → 'github:oxalica/rust-overlay/25d75be' (2026-04-20)
• Updated input 'uv2nix':
    'github:pyproject-nix/uv2nix/5707df9' (2026-04-09)
  → 'github:pyproject-nix/uv2nix/56cfeb9' (2026-04-16)

Author: github-actions[bot]