Function cfm_keystore_create 

#[unsafe(no_mangle)]
pub extern "C" fn cfm_keystore_create(
    out: *mut *mut FFIKeystore,
    backend_name: *const c_char,
    opts: *const c_void,
) -> u32

Create a keystore backed by backend_name (e.g. "memory").

Returns 0 on success, or a numeric ErrorCode on failure.