chore(nix): update `flake.lock`
Flake lock file updates:
• Updated input 'advisory-db':
'github:rustsec/advisory-db/09735e1' (2026-06-13)
→ 'github:rustsec/advisory-db/776615b' (2026-06-18)
• Updated input 'crane':
'github:ipetkov/crane/59a82a1' (2026-06-04)
→ 'github:ipetkov/crane/469fd08' (2026-06-18)
• Updated input 'fenix':
'github:nix-community/fenix/aad7d8b' (2026-06-13)
→ 'github:nix-community/fenix/ab90d06' (2026-06-20)
• Updated input 'fenix/rust-analyzer-src':
'github:rust-lang/rust-analyzer/3f92cd1' (2026-06-12)
→ 'github:rust-lang/rust-analyzer/501826b' (2026-06-20)
• Updated input 'nixpkgs':
'github:nixos/nixpkgs/e820eb4' (2026-06-08)
→ 'github:nixos/nixpkgs/d6df351' (2026-06-15)