GHSA-9HGC-G3W5-67CM ContextForge: DNS TOCTOU race condition causes SSRF protection bypass (`/admin/gateways/test`)

Summary The /admin/gateways/test endpoint validates submitted URLs by resolving the hostname at validation time and blocking private address ranges. The HTTP client independently re-resolves DNS at connection time with no IP binding between the two operations, creating a TOCTOU window exploitable...