Function unbounded_gdn_gate 

pub fn unbounded_gdn_gate(g_raw: f32, dt_bias: f32, a_log: f32) -> f32

Unbounded Qwen-GDN gate, kept only so the microtest can show the two laws diverge.

Atlas’s compute_gdn_gates stores exp(g); this returns g itself, matching the KDA convention where the exponential is taken inside the recurrence.