LeakProof (Challenge 01, Blast Radius Zero, Pattern A): finds revenue leaks in billing exports without letting the data leak. A model on Vultr Serverless Inference writes pandas code, the code runs in a throwaway gVisor container on a Vultr VM with no network, no secrets and hard limits, and a second model checks every claim against the real output. Each answer ships with a receipt (input hashes, code, output, limits) and nothing leaves without human approval. Solo team of Alan De Bortolo, Design Master Solutions LLC. Repo: github.com/DesignMaster-Solutions/leakproof