Add Mazza Group as x402 merchant example — 21 AI API endpoints for agent workflows

Mazza Group AI APIs (https://mazzagrp.com) is live with 21 x402-native API endpoints on Base mainnet (eip155:8453), USDC 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913, facilitator x402.org.

Endpoints cover agent-relevant workloads: strategy consultation, RAG, MCP evaluation, agent workflow design, competitive benchmarking, negotiation simulation, UI/UX generation, web agent planning, Monte Carlo simulation, time-series analysis, story generation, long-form Q&A, spreadsheet automation, SQL query generation, logic puzzles, verified knowledge recall.

All endpoints return standard HTTP 402 with x402 payment instructions. Pay-per-call, no API keys, no subscriptions — a good real-world merchant test target for AgentKit wallet flows. Happy to provide example agent code or test calls.