FIX: Make graders.py self-contained to fix Phase 2 validation failure

Fix: Entry point should reference main function for multi-mode deployment

Add [project.scripts] server entry point for OpenEnV validation

Fix pyproject.toml: Remove he_demo namespace for root-level structure

refactor: revert to root-level package structure with proper imports and hacky pyproject.toml setup

refactor: proper package structure - move he_demo package to dedicated folder

Add complete Energy & Memory RAM Optimization RL Environment