flake.lock: Update

Flake lock file updates:

• Updated input 'fenix':
    'github:nix-community/fenix/bfa40349cb508ebec2a8d0f89d65022967d28dc4?narHash=sha256-xpbGgQ6ymKvz/LQ3RrUTHdbRKWznZAbdaNAH7TdbKZs%3D' (2025-09-20)
  → '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/b12a1293473d4c1c74a63752184b8d21d32a6bde?narHash=sha256-PXDZtnSSNXIlTlytspxkTm/RENaQKdTJ44RGqm/LPLA%3D' (2025-09-19)
  → 'github:rust-lang/rust-analyzer/472037b789cf593172d6adf3b8d9f7a429f6cd9b?narHash=sha256-7StxDed3v2fAWLkl%2BHse9FlpjT7Dk7Cn/4vxTFyEhIg%3D' (2025-10-01)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/12bd230118a1901a4a5d393f9f56b6ad7e571d01?narHash=sha256-aBGl3XEOsjWw6W3AHiKibN7FeoG73dutQQEqnd/etR8%3D' (2025-09-19)
  → 'github:NixOS/nixpkgs/27ac93958969b5f3dccd654b402599cf3de633ac?narHash=sha256-hhM8SUI6kQMei5TImFdNQy9EDT8g2hAD161DUtbfAy0%3D' (2025-10-04)

Author: github-actions[bot]