Whitelist ownership grants via allow policies

Replace the deny-based restriction on granting OWNER with role-scoped
allow policies so authorization fails closed: admins may create and
update memberships only when the assigned role is not OWNER, and the
absence of a target role no longer implies permission.

To keep console UI gating accurate without loosening the base grants,
the permission field gains an optional typed options argument
(PermissionOptionsInput) that forwards target_role into the dry-run
authorization. Only the two role-related console calls (create user,
update membership) pass it; the OWNER option stays hidden for admins via
the existing assignable-roles helper.

Add a non-regression test that an admin cannot promote a member to OWNER
while still being able to change members between non-owner roles.

relay.config.json

@@ -39,7 +39,8 @@
         "Duration": "string",
         "BigInt": "number",
         "EmailAddr": "string",
-        "OAuth2Scope": "string"
+        "OAuth2Scope": "string",
+        "Map": "Record<string, string>"
       }
     },
     "trust": {