flake fails to build due to outdated go from nixpkgs input

[alanpearce]

In go.mod version 1.25.1 is required, however the flake's nixpkgs input only has 1.25-rc2, which causes a build failure for flake users:

go: go.mod requires go >= 1.25.1 (running go 1.25rc2; GOTOOLCHAIN=local)

This can be fixed by running nix flake update and committing the updated flake.lock. I would suggest adding this step to any workflow where dependencies are updated.