Add initial remote agent plugin docs

docs/device-agent/introduction.md

@@ -28,3 +28,7 @@ The [Quick Start Guide](/docs/device-agent/quickstart/) will get the Device Agen
 
 For more detailed information on installing and running the Device Agent, the full [installation guide](/docs/device-agent/install/overview/) has you covered.
 
+### Managing Existing Node-RED instances
+
+If you already have Node-RED running on your hardware that want to start managing with FlowFuse, you can use the Remote Agent plugin for Node-RED.
+This can be installed into Node-RED and get it connected to FlowFuse. Check the [Remote Agent documentation](/docs/device-agent/plugin/overview.md) for more information.

docs/device-agent/plugin/README.md

@@ -0,0 +1,10 @@
+---
+navGroup: RemoteAgentPlugin
+navTitle: Remote Agent Plugin
+redirect:
+  to: /docs/device-agent/plugin/overview
+layout: redirect
+navOrder: 8
+tags:
+  - noDropdown
+---

docs/device-agent/plugin/overview.md

@@ -0,0 +1,82 @@
+---
+navGroup: RemoteAgentPlugin
+navTitle: Overview
+navOrder: 1
+meta: 
+   description: Managing existing Node-RED installs using the Remote Agent plugin.
+   tags:
+      - installation 
+      - device agent
+      - flowfuse
+---
+
+# Remote Agent Plugin
+
+The Remote Agent plugin is an alternative option to the full Device Agent way of managing remote Node-RED instances.
+
+It is a plugin that can be installed into Node-RED, making it quick and easy to get an existing Node-RED connected to the platform without having to migrate to the Device Agent.
+
+::note
+The plugin does not provide all of the features of the Device Agent due to limitations of running inside of Node-RED. We will be added more features to continue expanding what is possible. See the [comparison with the Device Agent](#comparison-with-the-device-agent) section for more information on the differences.
+::
+
+
+
+## Requirements
+
+- Node-RED 4.1 or later
+- Node.js 22 or later
+- A FlowFuse account - either [FlowFuse Cloud](https://app.flowfuse.com) or a self-hosted
+  installation (FlowFuse 3.1 or later)
+
+## Installation
+
+Install the plugin into your Node-RED instance using the Palette Manager, or from the command
+line in your Node-RED user directory (typically `~/.node-red`):
+
+```bash
+npm install @flowfuse/nr-remote-agent
+```
+
+Restart Node-RED to load the plugin.
+
+## Connecting to FlowFuse
+
+In the status bar of the Node-RED editor you will see a 'Connect to FlowFuse' button.
+
+1. Open the Node-RED editor and click on the 'Connect to FlowFuse' button in the status bar. This will open the **settings** dialog for the remote agent.
+3. Enter the URL of your FlowFuse platform. This defaults to `https://app.flowfuse.com` for
+   FlowFuse Cloud - change it if you are using a self-hosted installation.
+4. Click **Connect**. A FlowFuse window opens for you to log in and choose the team and
+   application the instance should be added to.
+5. Once you complete the steps in FlowFuse, the settings pane will refresh to show the instance details, and the status bar button will show the state of the connection.
+
+
+### Disconnecting
+
+The same settings pane provides a **Disconnect** option. Disconnecting removes the local
+connection details - the instance cannot be reconnected to the same FlowFuse entry and will need
+to be registered again as a new Remote Instance.
+
+## What the plugin lets you do
+
+Once connected, the instance appears in your FlowFuse team and you can:
+
+- View the instance's logs remotely
+- Automatically capture a snapshots of your flows whenever you deploy changes
+- See a record of audit events from the instance in the FlowFuse audit log
+
+
+## Comparison with the Device Agent
+
+The [FlowFuse Device Agent](https://github.com/FlowFuse/device-agent) and this plugin both
+connect Node-RED to FlowFuse, but they take opposite approaches to who owns the runtime.
+
+The Device Agent provides a fully managed Node-RED environment; where you can deploy flows remotely,
+securely access the editor from anywhere and manage the Node-RED version and updates.
+
+This plugin doesn't provide all of these features yet, but we will be continuing to iterate to
+add more capabilities.
+
+Some features of the Device Agent will not be reproducable with the plugin due to the way it runs
+inside of Node-RED, rather than around the outside.