Decennium API Gateway

Multi-tenant gateway for Peqaboo, Petiva, Vetsheet and partner apps.

• Health check: GET /healthz
• Modules: /ai/** · /client/** · /admin/** · /merchant/** · etc.
• Required header on all requests: X-App-Source: peqaboo|petiva|vetsheet|...

See mini_app_protocol.md and multitenancy.ts for the contract.