kong-dynamic-upstream

Route requests to a different upstream per request, decided at the gateway:
by header value or regex, by authenticated consumer, or by a templated URL
built from request variables — with an SSRF-safe host allowlist enforced at
both config time and request time.

Two target modes:
- upstream: reference a Kong Upstream entity (load balancing, health checks)
- url: a literal or templated http(s) URL (Gravitee-style endpoint override)

First-match-wins rules, configurable no-match behavior (passthrough or 503),
DB-less/KIC friendly (no custom entities).