CVE-2026-56678: 9router: Kiro region injection allows authenticated SSRF with Authorization header forwarding

The Kiro API-key validation endpoint builds an upstream URL using a user-controlled region value. By supplying a crafted region such as kiro-canary.local:8443#, an authenticated attacker can cause 9router to send the Kiro validation request to an attacker-controlled host under the constructed codewhisperer.<region> hostname. The request forwards the submitted Kiro API key as an Authorization: Bearer header.