Add Grok Build

[shindgew]

Reference: https://docs.x.ai/build/cli/headless-scripting#acp

[shindgew]

unsupported archive type in URL: https://storage.googleapis.com/grok-build-public-artifacts/cli/grok-0.2.11-macos-aarch64

from #307.

[thibaudgg]

Same issue for me when trying to launch the grok-build ACP agent in latest Zed editor version (1.4.4).

unsupported archive type in URL: https://storage.googleapis.com/grok-build-public-artifacts/cli/grok-0.2.11-macos-aarch64