Set up Storybook with all UI components documented

[Marvell69]

There is no component library documentation. Without Storybook, new contributors can't discover existing components and often rebuild duplicates. A Storybook with all shared components accelerates development.

Requirements and context

• Install and configure Storybook 8 for Next.js
• Write stories for every component in src/components/
• Each story: default state, all variants, interactive controls for key props
• Add a11y addon for per-story accessibility checks
• Deploy Storybook to GitHub Pages on every merge to main
• Link from CONTRIBUTING.md and README.md

Suggested execution

git checkout -b docs/storybook-setup

• Install Storybook with Next.js framework plugin
• Write stories for all existing components
• Configure a11y addon
• Add GitHub Pages deployment workflow

Example commit message
docs: set up Storybook with stories for all UI components