CVE-2026-73840: OpenChoreo: Unauthenticated build/workflow trigger via git-provider confusion (webhook signature bypass)

The OpenChoreo autobuild webhook endpoint (POST /api/v1alpha1/autobuild) selected the git provider used to authenticate an incoming webhook from a client-supplied request header rather than from the target component’s configuration, and its Bitbucket provider accepted requests without a valid signature. A caller could set the X-Event-Key header to be treated as a Bitbucket webhook, bypassing the HMAC secret that otherwise protects GitHub and GitLab webhooks, and trigger a component build without authenticating.