Function assert_lifecycle_store_conformance 

pub async fn assert_lifecycle_store_conformance(
    store: &dyn LifecycleStore,
    present: &AgentId,
    absent: &AgentId,
)

Assert that a LifecycleStore implementation honors the trait contract.

Drives store through &dyn LifecycleStore and checks:

• register then heartbeat succeeds for a registered agent
• heartbeat on an unregistered agent returns StorageError::NotFound
• deregister removes the registration, after which heartbeat returns StorageError::NotFound
• deregister is idempotent for both registered and absent agents

present is registered and deregistered by the harness; absent must be an agent the store never holds. Panics on the first violated invariant.