CHEF-34733: Add Habitat plan for macOS aarch64-darwin platform

[sanghinitin]

Summary

Adds a new Habitat package plan for the macOS aarch64-darwin (Apple Silicon) platform, enabling hab pkg build for chef-cli on macOS ARM64.

Jira Ticket

CHEF-34733

Changes

• Created habitat/aarch64-darwin/plan.sh - full Habitat plan for macOS ARM64

Key Design Decisions

Area	Decision	Rationale
Compiler toolchain	Uses core/clang instead of core/gcc	core/gcc is unavailable on aarch64-darwin; clang is the native macOS compiler
Native extension build deps	Added core/make and core/cmake to pkg_build_deps	Required by libyajl2 gem which compiles yajl C library via cmake
CC/CXX export	Points to Habitat core/clang bin path, not xcrun	xcrun is unavailable inside Habitat build environment
PATH in do_prepare/do_build	Prepends cmake, make, clang bin dirs	Ensures native gem extensions find build tools during bundle install
HOME and GEM_SPEC_CACHE	Set to writable Habitat cache paths	Prevents Bundler Errno::ENOENT - getcwd and RubyGems permission errors
sed syntax	Uses GNU sed -i (no empty string arg)	Habitat provides GNU sed on PATH; BSD sed -i with empty arg causes read error
Runtime wrapper	Sets DYLD_LIBRARY_PATH for libarchive	macOS uses DYLD_LIBRARY_PATH (not LD_LIBRARY_PATH) for dynamic library resolution

Issues Resolved During Development

1. Errno::ENOENT getcwd - Bundler could not resolve working directory; fixed by exporting HOME to source cache dir
2. libyajl2 native extension build failure - extconf.rb requires cmake and make; added both to pkg_build_deps and ensured they are on PATH
3. sed read error - BSD sed syntax incompatible with GNU sed in Habitat; removed empty string argument from sed -i
4. rm typo - rm - rf (extra space) treated - and rf as filenames; fixed to rm -rf

Build Validation

$ hab pkg build .
# Build completes successfully
# Generated .hart artifact under results/
$ hab pkg install results/sanghinitin-chef-cli-6.1.34-*.hart
$ hab pkg exec sanghinitin/chef-cli chef-cli --version

Files Modified

• habitat/aarch64-darwin/plan.sh (new file, +138 lines)

Testing

Validated via hab pkg build . on macOS aarch64-darwin. Build completes, .hart installs, and chef-cli --version executes correctly via hab pkg exec.

[github-actions]

Simplecov Report

Covered	Threshold
98.51%	90%