Constant GDN_SCALAR_SPINE_PIPE 

pub const GDN_SCALAR_SPINE_PIPE: &str = "gated_delta_rule_chunk_delta_h_pipe";

The SCALAR spine entries qwen3_ssm::init can bind — ATLAS_GDN_PIPE=1, ATLAS_GDN_VTILE=1, and the default. Named here beside the tensor-core entry for the same reason that one is: the init route line and the handle are built from the same string or they drift apart.