Periplo: real-time status of the x402 facilitator and Bazaar on Stellar testnet.

Checks run on a schedule through GitHub Actions against the live testnet facilitator (periplo-testnet.fly.dev) and the project site. GitHub runs scheduled checks on a best-effort basis, so in practice they can be hours apart. Periplo runs on Stellar testnet only; there is no mainnet deployment yet.