Natural-language Q&A over the x402 Base settlements warehouse. POST {question}. Backed by 132M settlement rows on Cloudflare R2 + pre-aggregated daily_stats (388 days, May 2025 - Jun 2026), queried via Anthropic Sonnet + DuckDB. Returns {answer, sql_trace, model, upstream_ms}; sql_trace lets the caller verify the data path is real, not hallucinated. $0.05 USDC on Base.