Adds Authelia (forward-auth) and nginx portal container for single-endpoint authenticated access via Caddy reverse proxy. Configures Grafana auth proxy for header-based auto-login. Updates Vue UI base paths and API routes for /exabgp/ and /traffic/ subpath serving. Adds traffic-gen responder container on dedicated Docker network. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>