feat(homebrew): add dev cask install

[drew]

Summary

Add a Homebrew dev cask for macOS Apple Silicon that installs the rolling OpenShell dev CLI, gateway wrapper, and VM driver from a single GitHub release archive. Replace the generated formula/update-commit path with release automation that publishes the cask archive asset without committing on every release.

Related Issue

N/A

Changes

• Added Casks/openshell-dev.rb with version :latest and sha256 :no_check
• Added .github/workflows/homebrew-dev-cask.yml to repack dev CLI/gateway and vm-dev driver assets into openshell-homebrew-dev-aarch64-apple-darwin.tar.gz
• Removed committed formula files, the formula generator, and the formula update workflow
• Tightened release-vm-dev.yml to reject partial VM driver publishes
• Updated README and architecture packaging docs for the dev cask flow

Testing

• mise run pre-commit passes; attempted earlier, currently blocked locally by port 8080 already in use by Docker Desktop during sandbox_create_keeps_sandbox_with_forwarding
• Unit tests added/updated
• E2E tests added/updated (if applicable)
• git diff --check
• ruby -c Casks/openshell-dev.rb
• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/homebrew-dev-cask.yml"); puts "YAML OK"'
• brew style --cask nvidia/openshell/openshell-dev through a temporary local tap
• brew audit --cask --strict nvidia/openshell/openshell-dev through a temporary local tap
• brew install --cask not run locally because the new cask bundle asset is published by the workflow after merge

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)
• Architecture docs updated (if applicable)

[github-actions]

🌿 Preview your docs: https://nvidia-preview-pr-1071.docs.buildwithfern.com/openshell

[copy-pr-bot]

Auto-sync is disabled for draft pull requests in this repository. Workflows must be run manually.

Contributors can view more details about this message here.