Add content: Expo framework in React Native roadmap

Added comprehensive content explaining Expo framework and its ecosystem.

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Co-Authored-By: Claude <noreply@anthropic.com>

src/data/roadmaps/react-native/content/expo@yW7nDDJbjmm8XKJI0hq3Q.md

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-# Expo
+# Expo
+
+Expo is an open-source framework and platform built around React Native, designed to streamline the development process for cross-platform mobile applications. It provides a managed workflow that includes a comprehensive set of tools, APIs, and services for building, testing, and deploying apps for iOS, Android, and web—all using JavaScript or TypeScript.
+
+Expo simplifies mobile development by handling much of the native configuration behind the scenes. Developers can use the **Expo Go** app to preview and test their projects instantly on real devices, while the **Expo CLI** offers powerful commands for creating, running, and managing apps. The **Expo SDK** provides prebuilt modules for features like camera access, push notifications, geolocation, and more, allowing you to focus on app logic rather than native integrations. For production workflows, **EAS (Expo Application Services)** supports custom builds, over-the-air updates, and app store submissions.
+
+Learn more from the following resources:
+
+- [@official@Expo Documentation](https://docs.expo.dev/)