v0.1.0 — verify-only facilitator

Initial release. Verify-only x402 facilitator for Robinhood Chain (eip155:4663), settling in USDG.

🟢 Live: https://x402-facilitator-evm.purplesquirrelnetworks.workers.dev

The hosted x402.org facilitator serves only Base Sepolia; this one serves Robinhood Chain. USDG (the chain has no canonical USDC) implements EIP-3009, established by probing revert selectors since USDG is an EIP-2535 Diamond.

Scope: /verify only. No /settle — that needs a funded hot signer and is deliberately out of scope; the service holds no keys and CI enforces that invariant.

Verified in production: /health reports USDG domainSeparatorMatches: true; /verify returns insufficient_funds for a valid signature from an empty account and invalid_signature for tampered and cross-chain-replay signatures.

See CHANGELOG.