Function make_executor_factory 

pub fn make_executor_factory<A: FromPoolConfig + 'static>() -> TenantExecutorFactory<A>

Create a TenantExecutorFactory for an adapter that implements FromPoolConfig.

Captures the FromPoolConfig bound at construction time so that the factory can be stored as a type-erased closure in AppState.

The first argument is the tenant key, used for schema isolation naming.