Add self-contained Spinner component and integrate into components data

[VINAYMADIVAL]

Description

Added a new self-contained Spinner component to the UI library.
The Spinner provides a simple, accessible loading indicator using pure CSS (no external icon dependencies).
It aligns visually with other DevUI components and follows the same design, structure, and accessibility conventions.

Related Issue

Fixes #205

Changes Made

• Added src/components/Spinner.tsx — fully self-contained spinner component.
• Integrated Spinner entry in src/data/components.tsx for documentation and preview.
• Verified consistent sizing (sm, md, lg) and proper alignment in demos.
• Ensured accessibility with role="status" and aria-label.

Screenshots or GIFs (if applicable)

Checklist

• Only the necessary files are modified; no unrelated changes are included.
• Follows clean code principles (readable, maintainable, minimal duplication).
• All changes are clearly documented.
• Code has been tested and visually verified in dev build.
• No breaking changes are introduced to existing functionality.
• All new and existing tests passed (if tests exist).

Additional Notes

• The Spinner component does not depend on lucide-react or any prebuilt UI elements.
• Built to match the repo’s “self-contained components” guideline.
• Can be easily reused in loaders, Empty states, and buttons across the project.

[github-actions]

Great job, @VINAYMADIVAL! Thanks for creating the pull request.
Soon the maintainers/owner will review it and provide you with feedback/suggestions.
Make sure to star this awesome repository and follow the account!

• DevUI

[fahimahammed]

thank you

[VINAYMADIVAL]

🤝