Add Lima local virtualization runbook

[aronchick]

Summary

• add a Lima-based local virtualization runbook for macOS labs
• document installing Lima, creating five Ubuntu VMs, assigning stable SSH ports, and wiring Jetpack SSH overlay vars
• document installing Jetpack on the Mac/controller side and adding a local jetp alias when the upstream build installs jetpack
• clarify that this repo's Jetpack automation is distinct from NVIDIA Jetson JetPack
• link the runbook from the README and ignore local .local/ runtime state

Verification

• awk '/^```bash$/{inside=1; next} /^```$/{inside=0} inside{print}' docs/local-virtualization-lima.md | bash -n
• git diff --check
• limactl --version -> limactl version 2.1.3
• limactl start --list-templates | grep '^ubuntu-lts$'
• limactl create --help | rg -- '--ssh-port|--cpus|--memory|--disk|--arch'
• verified Jetpack recognizes jet_ssh_hostname, jet_ssh_port, jet_ssh_user, and jet_ssh_private_key_file from upstream riffcc/jetpack
• verified upstream Jetpack installation docs currently build from source with cargo install --path .

This PR is documentation-only; it does not create or modify any local VMs.

[Zorlin]

This inspired adding a bunch of functionality directly into Jetpack that should make these PRs and playbooks much simpler.

I will submit a revision soon.