Bump @parcel/transformer-coffeescript to 2.16.4

Parcel plugin versions must match core (2.16.4). Without this bump
`npm run build:parcel` fails with:
  Could not find module "@parcel/transformer-coffeescript" satisfying 2.16.4.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: ajaynes-godaddy