add UI components for AI demo

[myandrienko]

This PR adds UI components for the AI demo.

Aura

<Aura /> component is used as a visualization of an AI agent. It has an idle animation, and it optionally reacts to changes in volume of a given media stream.

Aura has two sets of styles. One for when an AI agent is speaking:

Screen.Recording.2025-01-30.at.04.24.16.mov

And one for when it is listening:

Screen.Recording.2025-01-30.at.04.27.15.mov

When a MediaStream is provided, Aura reacts to its volume (video with 🔊 sound):

Screen.Recording.2025-01-30.at.04.25.09.mov

Prop	Description
height	Component height in pixels. For performance reasons, component is rendered at 100x100 resolution and then scaled up. It always takes up 100% width, but height must be specified explictly.
activity	Switches style set: "listening" or "speaking"
mediaStream	(optional) When provided, Aura reacts to changes in audio track volume. Can be call participant audio or user mic audio.

AI Captions

Fancy styles for closed captions. New captions fly in, old captions dissolve. For the best effect, the caption queue must hold at least 6 captions.

Screen.Recording.2025-01-30.at.04.38.27.mov

Prop	Description
captions	An array of CallClosedCaption

[myandrienko]

Example usage ☝️

[myandrienko]

Closed in favor of https://github.com/GetStream/video-ai-demo/pull/1