## What changed
Add `.github/actions/setup-bazel-windows` to prepare MSVC, derive the Bazel Windows path, download the pinned Cygwin snapshot, and run the existing verified Windows dependency bootstrap. Export the Windows system root and host architecture for subsequent steps.
Use the action in the Bazel workflow and argument-comment lint action. Remove an unused `EnvironmentAttachment` import from the session tests.
GitOrigin-RevId: 8dc711dc9301bb44d49be3fdab79bd4ca981b7d0