Install and wire markstream-vue, markstream-react, markstream-vue2, markstream-angular, or markstream-svelte into an existing repository. Use when Codex needs to choose the right package, install the smallest framework-specific peer-dependency set, fix CSS/reset order, choose Vue 3 renderer and code-block modes, decide between `content`, `nodes`, and Vue 3 virtual-scroll coordination, or add a minimal working renderer example.