Set compute node access scope

Sets the access scope for a compute node. Only the owner of the node can modify the access scope.

Access scope levels:

• private: Only the owner can access the node
• workspace: All members of the workspace can access the node
• shared: Maintains existing user/team sharing but removes workspace access if any (use POST endpoints to add new shares)

Note: When setting to "shared", existing individual user and team permissions are preserved.
Use the granular POST/DELETE endpoints on /permissions/users and /permissions/teams to manage specific access grants.