docs: add devtools integration page

Author: onmax

docs/content/4.integrations/2.devtools.md

@@ -0,0 +1,21 @@
+---
+title: DevTools
+description: Inspect auth configuration and manage users/sessions during development.
+---
+
+This module integrates with [Nuxt DevTools](https://devtools.nuxt.com/) out of the box. No configuration needed.
+
+## Access
+
+Open Nuxt DevTools and click the **Auth** tab in the sidebar.
+
+## Available Tabs
+
+- **Config** - View auth endpoints, session settings, enabled plugins, and security configuration
+- **Sessions** - Browse and delete active sessions (requires NuxtHub DB)
+- **Users** - List and search users (requires NuxtHub DB)
+- **Accounts** - View connected OAuth providers per user (requires NuxtHub DB)
+
+::callout{icon="i-lucide-info"}
+Only available in development mode.
+::