dev/mock-api.mjs answers the endpoints the screens call, with surrogate data, and keeps what is changed in memory (zones, scopes, users, groups, rules, sessions, the cache). `npm run mock` starts it on 127.0.0.1:5380, where the dev server's proxy already points. .claude/launch.json starts the mock and the console together in the preview pane. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>