Wildcard projections now work in Depot CI expressions

Depot CI now supports GitHub Actions wildcard projections in runtime expressions. You can use expressions such as labels.*.name in step conditions, environment variables, and action inputs.

- name: Run for approved pull requests
  if: contains(github.event.pull_request.labels.*.name, 'approved')
  run: ./ci.sh

Previously, projections across arrays returned an empty value at runtime. They now match the behavior of GitHub Actions and Depot CI's compile-time expressions.