Defense in depth: the tenant router deletes every browser-supplied X-Hux-* header before asserting its own HUX identity headers, so no client can forge subject, trust class, or relay key. Regression covers X-Hux-Subject, X-Hux-Trust and X-Hux-Relay-Key forgeries. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BvMSXH8VH2tMWXanb8SJdf