Check whether a workspace handle is free (admin).
Admin
Check whether a workspace handle is free (admin).
Validates format + reserved words and checks global uniqueness across BOTH
the URL registry (tenants.slug) and the email registry
(tenant_email_slug), so the handle works for the URL and the email address
alike. Advisory only - set_slug re-checks atomically.
GET
Check whether a workspace handle is free (admin).
Authorizations
Personal Access Token. Send as Authorization: Bearer hq_pat_....
Query Parameters
candidate workspace handle