Refactor multiscale ray integration to the pipeline level so it is agnostic to the distributed environment

Move the multiscale Ray orchestration out of the core multiscale implementation and into the pipeline layer so the multiscale module is environment-agnostic. Define a clean execution interface that the pipeline can back with Ray, local multiprocessing, or a single-process runner. Remove direct Ray dependencies from core multiscale code, keep core logic pure , and update pipeline wiring/config to choose the distributed backend.