Design constraints for workspace inheritance chains

See discussion at !2115 (comment 635420) and at #978 (comment 634687)

Currently a user can use any accessible workspace to build an inheritance chain for a workspace they own, including having a workspace appear multiple times or setting up inheritance loops.

This is not necessarily an issue, as collection lookup can break loops and unaccessible workspaces are skipped during lookups.

I'm opening this issue to track more intentional design decisions, if any, for potential restrictions. Or alternatively, to explicitly decide that the status quo matches what we want.