Add read_ee_registry<T> helper that returns None and emits a job log in CE builds when a private registry is configured. Applied to all language executors: pip, npm/bun, deno, cargo, go, maven, nuget, powershell, and ruby. Maven settings.xml file write in monitor.rs is also gated. Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>