Function wait_for_registration_core 

pub async fn wait_for_registration_core(
    atlas: &mut AtlasClient,
    before: &ProviderRegistrationSnapshot,
    expected_provider_id: &str,
    who: &str,
) -> Result<RegistrationOutcome>

Poll atlas until the exact deployment instance has a new registration, then briefly settle to see if it also declares a */driver gRPC capability.

No terminal UI — pure RPC + sleep loop. Callers that want spinner / boot_progress output (rbnx CLI) wrap this with their own decorator. Soma calls it directly and logs through scribe.

Errors:

• timeout (no new provider before DRIVER_REGISTER_TIMEOUT),
• the expected provider vanished between matching and settling (crashed or was evicted by heartbeat lapse).

who is a free-form label included in error messages so the caller can tell which spawn this poll belonged to.