Exploration for implementing the first theme

[hnordt]

Summary

This is an exploration for implementing Hyperkernel's first theme.

• establish the initial canvas, surface, text, spacing, radius, border, typography, and shadow tokens
• add a responsive theme configurator that applies changes directly to the preview
• validate and persist theme choices in local storage, including reset and safe fallback behavior
• keep the page viewport fixed for the theme workspace

Impact

This creates a concrete first-theme prototype that can be evaluated before the theme contract is expanded or extracted into broader application infrastructure.

Validation

• npm run check
• npm run lint
• npm run build