Add README.md to ExportSwift example

Author: kateinoigakukun

Examples/ExportSwift/README.md

@@ -0,0 +1,16 @@
+# ExportSwift Example
+This example demonstrates how to export Swift functions to JavaScript.
+
+## Building and Running
+
+1. Build the project:
+   ```sh
+   env JAVASCRIPTKIT_EXPERIMENTAL_BRIDGEJS=1 swift package --swift-sdk $SWIFT_SDK_ID js --use-cdn
+   ```
+
+2. Serve the files:
+   ```sh
+   npx serve
+   ```
+
+Then open your browser to `http://localhost:3000`.