GitLab 18.6: From configuration to control

GitLab 18.6 enhances the GitLab Duo Agent Platform with the default availability of the Planner and Security Analyst agents, group-level awareness for the Planner agent, and support for the gpt-oss-120b open-source model for self-hosted deployments. Cloud-connected self-managed instances gain end-user model selection in the UI. Web IDE now supports air-gapped deployments. The modern interface is now the default for self-managed instances. Platform security is improved with custom business context labels for filtering security scan results.