x402-payai-setup

Wire x402 micropayments onto a provider's API via PayAI — point the agent-facing tools at the provider's OWN x402 endpoint so agents can pay-per-call. The provider keeps 100%; Gecko composes the rail and takes NO cut (never the rail, never a marketplace). Covers the 402 challenge/settlement handshake, mapping which operations are priced, and verifying a paid call OFFLINE before going live. Solana/x402-first, but the…