New Page: FlowFuse AI

### Description

I thought I'd opened an issue for this before, but apparently not. As we are shipping more AI feature _in product_ and enabling more use cases with Node-RED flows on FlowFuse, we really should have a `flowfuse.com/product/ai` (or some equivalent) that showcases the great stuff you can do with AI on FlowFuse.

A quick brain dump of the areas AI is available:

### Developer Experience

- Shinier/marketing version of our docs (7 x use cases so far): https://flowfuse.com/docs/user/assistant/

### Integrating AI with your Applications

- LLMs (RAG/Chat Blueprints)
- (Coming Soon...) MCP Server Nodes
- (Coming Soon...) ONNX Node
- (Coming Soon...) Image Classification, Object Detection & Depth Estimation Nodes

#### Nice to Haves

- Langchain?? Quite manual currently, but we could put out content here
- Other models:
- Text to Speech
- Speech to Text
- Predictive Analytics

### Epic/Story

_No response_

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate