Update some core concept docs

Author: Shellishack

README.md

@@ -11,6 +11,7 @@ Pulse Editor
 
 <div align="center">
 
+[![Static Badge](https://img.shields.io/badge/docs-8A2BE2?style=for-the-badge)](https://docs.pulse-editor.com)
 [![Discord](https://img.shields.io/badge/Discord-%235865F2.svg?style=for-the-badge&logo=discord&logoColor=white)](https://discord.gg/s6J54HFxQp)
 [![Licence](https://img.shields.io/github/license/Ileriayo/markdown-badges?style=for-the-badge)](./LICENSE)
 

docs/docs/guide/develop-extensions/_category_.json

@@ -1,4 +1,8 @@
-# Develop Extensions
+---
+sidebar_position: 5
+---
+
+# Development Guide
 
 ## Choose your framework
 

docs/docs/guide/develop-extensions/index.md

@@ -0,0 +1,11 @@
+# Develop Extensions with React
+
+## Create an extension project with React
+```bash
+pulse create --framework react
+```
+
+## React Library
+The `@pulse-editor/react-api` is automatically installed if you create a project using the command above.
+
+In this package, it provides many useful hooks for your extension to interact with Pulse Editor Core via [Inter-Module Communication (IMC)](/docs/guide/pulse-editor-app/extension-system/imc). 

docs/docs/guide/develop-extensions/react.md

@@ -1 +1,5 @@
+---
+sidebar_position: 1
+---
+
 # Concepts

docs/docs/guide/develop-extensions/react/_category_.json

@@ -0,0 +1,13 @@
+---
+sidebar_position: 1
+---
+
+
+# Pulse Editor Core
+
+## One Codebase, Every Platform
+Pulse Editor Core is developed using modern web technologies with Next.js, enabling a single codebase for all platforms. Its architecture is built around abstract interfaces, allowing native-specific implementations to plug in cleanly while maintaining a consistent core logic.
+
+## Native Support via Electron and Capacitor
+After the app is built with Next.js, it is deployed to native platforms using Electron for desktop and Capacitor for mobile. This setup enables full native functionality across devices while preserving the benefits of a unified codebase.
+