feat(directory-sync): support on-demand directory syncing

[katie-west]

Why

I added workos.directorySync.syncDirectory(id) so Node applications can request an on-demand directory sync through the public API.

• It returns the typed queued response from HTTP 202 and uses the existing SDK error classes, including RateLimitExceededException.retryAfter for cooldowns.
• The method is provider-neutral; the API initially supports Google Workspace. Acceptance does not mean the pull has completed.
• Existing directory types, serializers, and methods remain unchanged.

Not covered by CI

• Release after the public endpoint is deployed and verify against a configured Google Workspace directory.
• Confirm the API reference's Node example calls syncDirectory(id) and explains queued versus completed.

Proof

No live Google Workspace request captured. Before release, call the method with a linked directory, inspect the queued result, and confirm a subsequent real pull completes. Repeated calls should expose the existing conflict or rate-limit exceptions, not another success response.

Fixes FEAT-3084

[linear-code]

FEAT-3084

[katie-west]

Coordinated draft set: API/docs https://github.com/workos/workos/pull/74202 and SDK generation policy workos/openapi-spec#193. Keep releases after the API deployment. The API draft contains the full companion list; no SDK packages have been published.