Reproduce Thm 4.6: value-matrix fine-tuning zero-shot error = sigma^2+(2/(d+4))||theta0||^2; measured 0.3204 vs theory 0.322 (d=5), matches across d/||theta0|| sweep

Update logbook: Repro - Fine-Tuning Without Forgetting In-Context Learning (jl2f2Y3iuC)

Update logbook: Repro - Fine-Tuning Without Forgetting In-Context Learning (jl2f2Y3iuC)

Update logbook: Repro - Fine-Tuning Without Forgetting In-Context Learning (jl2f2Y3iuC)