Auto sync env clients

[burtenshaw]

This PR makes core EnvClient calls auto-dispatch between sync and async usage so simple synchronous callers no longer need to wrap clients with .sync().

[bot-ci-comment]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[burtenshaw]

cursor review

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 2 potential issues.

^{Bugbot Autofix is ON, but it could not run because the branch was deleted or merged before autofix could start.}

^{Reviewed by Cursor Bugbot for commit ed9c3ab. Configure here.}