switch internal tools over to `go tool`

https://www.jvt.me/posts/2025/01/27/go-tools-124/ has a good description of how and why. this probably means gqlgen (used for tests), golangci-lint, maybe more

Start with the linked Go tools article, then inspect how gqlgen is used for tests and how golangci-lint is invoked. Identify any additional internal tools in the repository and migrate the relevant tool setup to Go's tool mechanism; done means the listed tools work through the new setup and tests and linting still run.

Written by the indexing model from the issue text.