docs: add macOS menu bar app section to README

Add documentation for the companion menu bar app that provides
native macOS controls for managing the proxy server.

README.md

@@ -343,6 +343,23 @@ Refer to `config.example.json` for a complete list of fields and documentation.
 
 ---
 
+## macOS Menu Bar App
+
+For macOS users who prefer a native experience, there's a companion menu bar app that provides quick access to server controls without touching the terminal. Get it from: [antigravity-claude-proxy-bar](https://github.com/IrvanFza/antigravity-claude-proxy-bar)
+
+![AntiGravity Claude Proxy Bar](https://github.com/IrvanFza/antigravity-claude-proxy-bar/blob/main/images/application.png?raw=true)
+
+### Key Features
+
+- **Server Control**: Start/stop the proxy server with a single click or ⌘S shortcut.
+- **Status Indicator**: Menu bar icon shows server running state at a glance.
+- **WebUI Access**: Open the web management console directly from the menu.
+- **Port Configuration**: Customize the proxy server port (default: 8080).
+- **Auto-Start Options**: Launch server on app start and launch app at login.
+- **Native Experience**: Clean, native SwiftUI interface designed for macOS.
+
+---
+
 ## API Endpoints
 
 | Endpoint          | Method | Description                                                           |