Routing

Tenant routing + Cognito config lookup.

📄️Resolve tenant routing + Cognito config

Returns the public-safe routing fields a frontend needs to bootstrap a tenant session: the tenant's backend origin and Cognito hosted-domain / app client ID. Result is cached in-process for 60s. Returns 404 if no `ROUTING` or `COGNITO` row exists for the tenant, or if either is marked `active=false`.