Properly categorize all dependencies for npm library distribution

Refines the dependency fix from the initial PR to follow npm library best practices:

- Add peerDependencies: react, react-dom, @fluentui/react, office-ui-fabric-react
  (consumers provide these; prevents duplicate React bundling - fixes #141)
- Keep only runtime dependencies: file-saver, xlsx (used in gridexportutil.tsx)
- Move all build tools (@babel/*, typescript, webpack-cli, cpx, react-scripts),
  test libraries (@testing-library/*), type definitions (@types/*), and
  demo-only packages (react-toastify, web-vitals) to devDependencies

This eliminates the 'Invalid Hook Call' error caused by bundling a separate
copy of React when the library is consumed as an npm dependency.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Alexander Elguezabal (from Dev Box)