Recursive Mamba update rebuilds reasoning stack

Promising experiment, but still more lab notebook than proven breakthrough.

• –Freezing the backbone while training a tiny head is a sensible way to isolate whether recursion helps without wrecking base language skill.
• –The padding and `<THINK>` target bugs are a big deal: they show how easily small curriculum mistakes can manufacture illusory progress.
• –The unit-circle rotator and fused JIT kernel sound like useful stability and speed work, but they need ablations to prove they help beyond keeping training afloat.
• –The “Mamba-3-style” wording reads like the author’s own custom label, so I’d treat it as an experimental architecture, not an established upstream release.
• –The real test is still ahead: whether N=3 and beyond beat strong baselines on held-out reasoning tasks, not whether the loop can be made to train.