Clean React Tests

React tests should describe what the user can observe and do. Prefer Testing Library queries that match accessible UI and user-event interactions that match real workflows.

R10: Query Priority

Prefer:

1. getByRole with accessible name
2. getByLabelText
3. getByText for non-interactive copy
4. getByTestId only when user-facing queries are not practical

// Bad - coupled to markup
expect(container.querySelector(".save-button")).toBeTruthy();