Build an NPM package for the trajectory visualizer

[xingyaoww]

I want to publish trajectory-visualizer to npm so that i can:

1. npm install trajectory visualizer easily
2. and a simple way to launchthing the trajectory visualizer with an argument e.g., traj-viz --file XXX.json where XXX.json is a local eventstream file. This will automatically open trajectory visualizer on that file to display its content.

Currently we already support load from URL https://github.com/All-Hands-AI/trajectory-visualizer?tab=readme-ov-file#method-2-load-from-a-url -- I imagine to implement 2 we can re-use this function

[openhands-ai]

I'm on it! xingyaoww can track my progress at all-hands.dev