Include gh-aw-detection version in generated aw_info metadata

[Copilot]

This updates aw_info.json to carry the gh-aw-detection binary version so downstream telemetry/reporting can distinguish detector runtime versions. The version is now propagated from workflow generation into runtime metadata.

• aw_info payload extension

  • Added detection_version to actions/setup/js/generate_aw_info.cjs.
  • Value is sourced from GH_AW_INFO_DETECTION_VERSION.

• Compiler env wiring

  • Updated pkg/workflow/compiler_yaml.go to emit GH_AW_INFO_DETECTION_VERSION in the generate_aw_info step env block.
  • Value is set to DefaultThreatDetectVersion when features.gh-aw-detection is enabled, otherwise empty.

• Coverage updates

  • Extended JS and Go tests to assert the new metadata field and env emission behavior.
  • Refreshed affected wasm golden fixtures due to generated env changes.

const awInfo = {
  // ...
  awf_version: process.env.GH_AW_INFO_AWF_VERSION || "",
  awmg_version: process.env.GH_AW_INFO_AWMG_VERSION || "",
  detection_version: process.env.GH_AW_INFO_DETECTION_VERSION || "",
};