Remove npm version restriction in `nachet-frontend`

[k-allagbe]

Description

package.json specifies:

  "engines": {
    "npm": "^9.8.1",
    "node": "^18.16.0"
  }

This was done due to some dependency issues with create-react-app. We've now moved to Vite, so it is no longer necessary. Also there are major new versions for npm and node.

Tasks

• [ ] Remove the restriction.
• [ ] Ensure the app builds and runs.
• [ ] Ensure tests pass.
• [ ] Update docs if necessary.

Acceptance Criteria

• npm 9.8.1 is no longer enforced.