feat(hpc): add structured env/hpc config and requirements export script

- env/hpc/modules.txt: curated list of HPC EasyBuild modules loaded by vsc-venv
- env/hpc/requirements.txt: pip packages not covered by HPC modules (auto-generated)
- scripts/export_hpc_requirements.py: developer utility to regenerate requirements.txt
  from pyproject.toml; to be called by CI when pyproject.toml changes

env/hpc/requirements.txt

@@ -0,0 +1,9 @@
+biorobot==0.4.2
+cleanrl>=0.4.8
+evosax==0.2.0
+gymnasium>=1.2.3
+ipykernel==7.2.0
+mediapy==1.2.6
+pyopengl>=3.1.10
+pyopengl-accelerate>=3.1.10
+tyro>=1.0.10