aave-v3-arbitrum-usdc: USDC supply APR, time-weighted over 2026-09-28→2026-09-29, signed. Cheaper than the agent turns you'd burn finding the contracts, decoding ray-scaled rates, sampling the series, and time-weighting it — you trust the math, not us. Verify it offline — schema, every published figure recomputed, and the secp256k1 signature — with no API call and no trust in us.