Add tree-shaking demo

Author: rebeccaalpert

README.md

@@ -22,6 +22,27 @@ import '@patternfly/chatbot/dist/css/main.css';
 
 If you are using React 17, ChatBot currently has a dependency on [react-markdown](https://github.com/remarkjs/react-markdown) that relies on React 18 and 19. There is an older version of react-markdown (8.0.7) that supports 17, but it does not have support for 19. You should be able to add `"react"` and `"react-dom"` of the appropriate version to the `overrides` section of your `package.json` file if you need to use ChatBot with 17.
 
+### Tree-shaking
+
+Import each component from its dynamic entry point to keep bundle size minimal:
+
+```tsx
+import ChatbotToggle from '@patternfly/chatbot/dist/dynamic/ChatbotToggle';
+```
+
+Named imports from the root barrel also tree-shake with modern bundlers that respect the package `sideEffects` field.
+
+`CodeModal`, `PreviewAttachment`, `AttachmentEdit`, and `tracking` are not exported from the root barrel — import them from `dist/dynamic/<Component>` instead. See `packages/module/patternfly-docs/content/extensions/chatbot/tree-shaking.md` for migration details.
+
+To verify tree-shaking in this repo:
+
+```bash
+npm run build -w @patternfly/chatbot
+npm run analyze:tree-shaking
+```
+
+See `packages/tree-shaking-demo/README.md` for full results and best practices.
+
 ## Contribution guide
 
 ### AI-assisted development guidelines

jest.config.js

@@ -30,7 +30,8 @@ module.exports = {
   modulePathIgnorePatterns: [
     '<rootDir>/packages/*.*/dist/*.*',
     '<rootDir>/packages/*.*/public/*.*',
-    '<rootDir>/packages/*.*/.cache/*.*'
+    '<rootDir>/packages/*.*/.cache/*.*',
+    '<rootDir>/packages/tree-shaking-demo/*.*'
   ],
   moduleNameMapper: {
     '\\.(css|scss)$': 'identity-obj-proxy',