HPC systems registry

labflow reads ~/.claude/contexts/hpc-systems.yaml. Each entry is a SystemSpec with:

• queueing_system: slurm or null (local)
• arch, node (cores, memory_gb, gpus)
• partitions (dev / normal / large)
• env (backend + per-backend config)
• modules (mpi, compiler, cuda)
• scratch path (absolute, with ${project} interpolation)
• template (default Jinja2 template name)

See the full schema in the design spec: Assets/claude/docs/specs/2026-04-20-scientific-software-infrastructure-design.md §6.