docs(mcp): add CODEX tab and installation instructions to documentation

Author: chishiyac

apps/www/content/docs/mcp.mdx

@@ -28,6 +28,7 @@ This is useful for Magic UI because you can now give your AI-assisted IDE direct
     <TabsTrigger value="cursor">Cursor</TabsTrigger>
     <TabsTrigger value="windsurf">Windsurf</TabsTrigger>
     <TabsTrigger value="claude">Claude</TabsTrigger>
+    <TabsTrigger value="codex">CODEX</TabsTrigger>
     <TabsTrigger value="cline">Cline</TabsTrigger>
     <TabsTrigger value="roo-cline">Roo-Cline</TabsTrigger>
   </TabsList>
@@ -51,6 +52,13 @@ This is useful for Magic UI because you can now give your AI-assisted IDE direct
     npx @magicuidesign/cli@latest install claude
     ```
 
+  </TabsContent>
+  <TabsContent value="codex">
+
+    ```bash
+    npx @magicuidesign/cli@latest install codex
+    ```
+
   </TabsContent>
   <TabsContent value="cline">