We need to upgrade from React 18 to 19. There should be no breaking API changes, but I've some runtime issues (related to useEffect hooks) in other projects I migrated, we should also test for regressions carefully.

Note: We have one dependency which is a bit picky about the React version: @react-spring/web is currently at v9.7.5. This version is the latest compatible with React 18, but not compatible with React 19. Once we've migrated to React 19, make sure to upgrade @react-spring/web to v10.x, which is compatible with React 19, but not 18!