feat: add a cart ✨ — the tooling-friendly placement: commitlint,
changelog generators and git log --grep '^feat' all still see a clean
conventional subject at the start of the line.
✨ add a cart — the emoji stands in for the type word.
You still writefeat: add a cart, and it is still validated as
such; only what gets stored differs. Know what it costs: the stored
history is no longer parseable by conventional-commit tooling, because
the type is now carried by an emoji. This mode chooses how the log looks
over what can read it, and that is a real trade, not a free one.