feat: implement difficulty-based reward weighting and update environment configuration schema

build: install gcc and libc6-dev in Dockerfile to support Rust linking

refactor: update inference script to support multi-problem evaluation and synchronous execution

feat: add README and update Dockerfiles to install algo_reasoning_env via pyproject.toml

feat: add app.py entry point, configure Docker for local package installation, and update README for HuggingFace Spaces deployment

initial clean commit