The Go SDK declared its module as github.com/vectorize-io/hindsight-client-go,
but that repository doesn't exist. Update to
github.com/vectorize-io/hindsight/hindsight-clients/go to match the actual
monorepo path, enabling standard `go get` imports with directory-prefixed tags.
Also enables isGoSubmodule in the OpenAPI generator config and updates all
import references across tests, docs, and the client generation script.
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>