Install Boost Regex dependency in CI

[Copilot]

The build GitHub Actions job failed because generated C++ runtime tests link against boost_regex, but the Ubuntu runner did not install the Boost Regex development package.

• CI dependencies
  • Adds the missing native package required by generated C++ test binaries.
  • Runs apt-get update before package installation to ensure the runner has current package metadata.

- name: Install Dependencies
  run: sudo apt-get update && sudo apt-get install -y libboost-regex-dev

[marron-at-work]

Just went ahead with boost all for simplicity.