contrastive_step/entropy_step wrote a fake gradient (grad += v*0.01) unrelated
to the stated objective, so any "TTA improves the metric" was unsupported. The
*_loss functions are now pure evaluators of the real objective; adapt() descends
them with a central finite-difference gradient of that exact loss, so "the
adaptation loss decreases" is now a real, reproducible measurement.
Honest scope caveat (documented): this minimizes a self-supervised proxy over a
LoRA bottleneck on raw CSI; it is NOT wired to the pose model and there is NO
measured end-to-end PCK gain on WiFi pose from this path.
Tests: contrastive_loss_decreases, entropy_loss_decreases (real gradient steps
don't increase the loss), reported_loss_is_the_real_objective_not_a_placeholder.
Co-Authored-By: claude-flow <ruv@ruv.net>
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