Improved Node-RED within FlowFuse

### Description

In hosting Node-RED through FlowFuse, we should explore opportunities to provide an improved Node-RED experience. This Epic captures these ideas.

### Existing

- Immersive Editor: Provides a FF tray above the NR Editor that provides quick access to the Node-RED logs, Snapshots, Assets, etc.
- Project Nodes: Provide a channel by which to communicate between Devices and Instances, and (soon) publish direct to the MQTT Broker
- FlowFuse AI Assistant: Available in FlowFuse Cloud, although can be configured for self-hosted, but requires manual communication with us.

### Opportunities

- Self Hosted FlowFuse Assistant
- FlowFuse Nodes
- Rebranding the "Project Nodes" to be more intuitive as to what they offer Node-RED users, e.g. to "Send", "Broadcast" and "Listen"
- Machine Learning & Predictive Analytics: Ideally for use with UNS/MQTT feeds
- Some combination of [Async API node generation idea](https://github.com/dalelane/node-red-contrib-plugin-asyncapi) with the incoming [Schema Documentation for FlowFuse.](https://github.com/FlowFuse/flowfuse/issues/4867)

```[tasklist]
### Opportunities
- [ ] Self Hosted FlowFuse Assistant
- [ ] Rebrand Project Nodes
- [ ] Machine Learning & Predictive Analytics
- [ ] Payload Validation on UNS/Broker
- [ ] https://github.com/FlowFuse/flowfuse/issues/5095
```

### Which customers would this be available to

None

Start by reviewing the existing Immersive Editor, Project Nodes, and FlowFuse AI Assistant described in the issue, then follow the linked AsyncAPI, schema documentation, and issue 5095 references. The epic is done only after one opportunity has been selected and given a concrete scope, entry point, and acceptance criteria in a focused issue.

Written by the indexing model from the issue text.