Get a specific build by CalVer version.
Syncs build status from Cloud Build and returns the build info.
Args: provider_id: Unique identifier for the provider. version: CalVer version string (YYYYMMDD.HHMMSS). service: Provider service for build operations.
Returns: BuildInfo for the requested build.
Raises: HTTPException: 404 if build not found.
Successful Response
Build information exposed via API.
Excludes internal fields (image, cloud_build_id) that should not be exposed to users.