Add RealityStream AI Assistant Agent

[Sampreethi66]

Summary

Added a Node.js-based RealityStream AI Assistant Agent.

Features:

• Generates parameters.yaml examples
• Recommends ML models
• Explains RealityStream workflow steps

Notes

The assistant uses Gemini API when quota is available.

If API quota is unavailable, it returns a fallback YAML response for local testing.

Testing

Tested locally with:

npm start

[ModelEarth]

Let's not add NodeJS to the static "realitystream" repo.

For anyone interested in carrying this forward:
Create a new repo called "realitystream-node" in your github account.
Move the NodeJS work there. Later we'll move it to a repo in the ModelEarth account.