CAS store and engine plugins under the legacy ~/.cache layout

Cache and plugin directories follow platform conventions

Terragrunt's global cache directory now resolves to the platform's user cache location instead of a hard-coded ~/.cache/terragrunt. On Linux this honors XDG_CACHE_HOME (still ~/.cache/terragrunt by default), on macOS it resolves to ~/Library/Caches/terragrunt, and on Windows it resolves under %LocalAppData%. The CAS content store, the auto provider cache, and the IaC engine plugin directory all move with it.

Existing caches at the previous locations are not migrated. They become orphaned and continue to consume disk space until removed.

Consider deleting the old paths to reclaim that space if you are on macOS or Windows, or have configured a custom XDG_CACHE_HOME:

# CAS store and engine plugins under the legacy ~/.cache layout
rm -rf ~/.cache/terragrunt