setup-go's built-in module cache defaults to keying only on the root go.sum, so the infra/ module's heavy Pulumi SDK dependencies (pulumi/sdk, pulumi-cloudflare, pulumi-gcp) re-downloaded on every run. Set cache-dependency-path to hash both go.sum and infra/go.sum so infra/'s deps are restored from cache. The cache warms on the first (cold) run; the speedup lands on subsequent (warm) runs. Closes #32 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>