Remove CodeBuild

Editor assessment

The subject states the removal plainly: CodeBuild is removed from CI. The body then supplies exactly what a reader wants: CodeBuild was very old, no longer worked, and was not used. That is a complete motivation in one sentence — no padding, no noise. The ci type is precisely right, and the imperative Remove is clean. No scope is needed for a tooling removal, and no footers are required. Every element a reader could ask for is present: what, where, and why. An exemplary small commit.