Integrate Storybook for UI component development and documentation

[code-by-sia]

Summary

Integrate Storybook to support isolated UI component development, visual testing, and UI documentation.

Goals

• Establish a component-driven UI workflow.
• Improve developer productivity during the React UI migration.
• Create living documentation for UI components.
• Enable visual review and regression testing.

Scope

• Configure Storybook in the project.
• Add stories for shared UI components such as buttons, toolbars, dialogs, menus, panels, icons, and spreadsheet-related controls.
• Document component states, variants, and interactions.
• Integrate Storybook into CI where practical.
• Publish Storybook as a static site or development artifact.

Suggested acceptance criteria

• Storybook runs locally via npm scripts.
• Core reusable UI components have stories.
• Component usage examples are documented.
• Storybook works alongside the React UI migration effort.
• CI can build Storybook successfully.

Notes

This issue focuses on the UI layer and complements the React migration effort.