Create a sandbox Item of the given type, dropped into the per-user folder and stamped with the manualSandbox flag so cleanup can find it later.
Foundry Item type ("feature", "action", …).
Optional
Extra data merged onto the create payload (system, name, etc.). Defaults are sensible for the pilot tours; callers usually leave this empty.
Create a sandbox Item of the given type, dropped into the per-user folder and stamped with the manualSandbox flag so cleanup can find it later.