Better tree-shakeability, React 19, typed JSX-components

[splashdust]

This PR bumps React to version 19 for the mono repo. This means that tests and builds of the React library will run against v19 going forward.

There are also a few other changes included, aimed to improve developer experience:

"Batteries included" for React:

Since React 19 natively supports custom elements, we can export typed JSX components from the Core library instead of relying on Lits custom element wrapper. This means that it will no longer be necessary to create local wrappers for React. Instead components can just be imported from @sebgroup/green-core/react:

import { GdsButton } from '@sebgroup/green-core/react'

<GdsButton rank="secondary" onClick={() => console.log('Hello')}>Click me!</GdsButton>

Move towards tree-shakeable components:

This changes the way components are defined in the custom elements registry. Previously it was only possible to import components with the define step was a mandatory side-effect. This meant that bundles could not remove any Green Core components, even if they were not used or referenced.

In this PR, an alternative, side-effect free, way of importing components has been added. Each component now has a file called [name].component.ts which holds the actual implementation, but does not define the custom element. Each component class now also has a static method called define() which can be used to define the element. The old [name].ts module will still call the define step, so existing code should remain unaffected.

All the side-effect free components are then bulk exported from @sebgroup/green-core/pure so that imports can be grouped.

Here is how to use the new side-effect free imports:

// This imports the component classes with no side-effects
import { GdsButton, GdsDropdown } from '@sebgroup/green-core/pure'

// This is required before the components can be used. This call defines the element in the
// custom elements registry.
GdsButton.define()
GdsDropdown.define()

For screnarios where bundle size is irrelevant, all components (including icons) can be imported from @sebgroup/green-core/everything. Use with caution, as this will inflate your bundle size with ~600kb:

import "@sebgroup/green-core/everything"

[green-design-system-bot]

🦋 Changeset status

Based on the included changeset, the following releases will be published as a result of this PR:

• @sebgroup/green-core: 1.69.4 → 1.70.0 (minor bump)
• @sebgroup/green-angular: 5.6.0 → 5.6.1 (patch bump)
• @sebgroup/green-react: 3.25.0 → 3.26.0 (minor bump)

Note: If unpublished changesets where merged to main after the first commit of this PR, this
list will include those changes in addition to the ones specific to this PR.

[Copilot]

Pull Request Overview

This PR upgrades React to v19 and introduces tree-shakeable, typed JSX components that improve developer ergonomics. Key changes include bumping to React 19, exporting direct JSX component wrappers from the Core library, and providing a side-effect free way to use components via pure imports.

Reviewed Changes

Copilot reviewed 957 out of 959 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
apps/react-lib-dev/src/design/blocks/sidebar.tsx	Introduces the Sidebar component with routing and layout changes.
apps/react-lib-dev/src/design/blocks/header.tsx	Implements the Header component with a responsive menu toggle.
apps/react-lib-dev/src/config/routes.tsx	Defines the new route configuration with nested subRoutes.
apps/react-lib-dev/src/components/green-core-form.tsx	Updates the form example to use new JSX wrappers and a dynamic field reflection.
apps/react-lib-dev/src/app/app.tsx	Refactors the App component to integrate the new Header/Sidebar layout and dynamic route rendering.
apps/docs/utils/import/components.tsx	Switches from dynamic imports to static re-exports from the new Core react package.
apps/docs/app/layout.tsx	Wraps the layout in the new theme component to enforce the design version.
.changeset/*	Updates documenting the React 19 upgrade and treeshaking improvements.

Files not reviewed (2)

• apps/docs/tsconfig.json: Language not supported
• apps/react-lib-dev/project.json: Language not supported

Comments suppressed due to low confidence (1)

apps/react-lib-dev/src/components/green-core-form.tsx:231

• The component 'CoreFlex' is used without an explicit import; please ensure that it is properly imported to avoid runtime errors.

<CoreFlex align-items="center" gap="m">

[astrit]

Looks good to me, tremendous amount of work here very excited to upgrade docs to latest version 👌