docs(agents): require standalone preview assets

Author: ericyangpan

AGENTS.md

@@ -98,4 +98,6 @@ const tComponent = useTranslations('components.navigation.breadcrumb')
 ## Development Workflow
 
 - **Development server:** Do not start `npm run dev` automatically. User will start it manually when needed.
+- **Standalone preview assets:** Before starting `.next/standalone/server.js`, sync `public/` into `.next/standalone/public/` and `.next/static/` into `.next/standalone/.next/static/`. Repeat this after every production build because Next.js regenerates `.next/standalone/`. Never start the standalone server without these assets.
+- **Standalone preview verification:** After starting or restarting a standalone preview, verify that one representative page returns `200` and that a stylesheet referenced by that page returns `200` with a CSS content type. When using tmux, include the asset sync in the pane start command.
 - **Git commits:** Do not create commits autonomously. Always ask the user before committing changes.