Delete marin/run/ray_run.py

Removes 419 LOC of Ray-based job-submission CLI with zero in-repo
callers. Doc and runbook references were swept in #5076; the canonical
replacement is `uv run iris --cluster=marin job run --no-wait ...`.

Part of the Ray-removal effort tracked in #4453.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: yonromai