Previous advice was completely wrong. The facts:
- VM.Monitor permission doesn't exist in PVE 9 (was removed)
- It was replaced with VM.GuestAgent.Audit
- But even with correct permissions, API tokens CANNOT access guest agent data on PVE 9
- This is Proxmox bug #1373 with NO working workaround for API tokens
- Users must accept 0% VM disk usage on PVE 9 until Proxmox fixes it upstream
Updated all documentation and error messages to reflect this reality instead of giving false hope about non-existent workarounds.