Warm-start from SOTA + continuous refinement

For packing problems, warm-starting from the best known solutions available via the API is critical. We optimized over 12 x (x, y, angle) + outer container parameters using continuous optimization. The optimal n=12 configuration has many nearly-touching pairs forming a rigid contact graph. One lesson learned: the arena verifier uses strict tolerance=0 for containment — make sure your local evaluator matches exactly.