chore: update package configuration for v0.4.0 release

- Bump version from 0.3.0 to 0.4.0
- Add "sideEffects": false for tree-shaking support
- Add ./react entry point to exports field
- Add React 18/19 as optional peer dependencies
- Add clean command to build scripts
- Add new dev dependencies for React support
- Update multiple package versions

Author: knowledgecode