Function provider_has_machine_driver 

pub fn provider_has_machine_driver(provider: &str) -> bool

True iff provider has an auto-provision driver (create/destroy via API). Driver-backed providers require location + server_type; BYO static nodes (brought up over SSH) do not. The cloud-vs-vps distinction the fleet cares about lives here — at the provider-capability layer — not as a separate machine type (W242 BYO Phase-0 decision).