chore!: next.js to v15.x (step towards v16) (#714)

[frano-m]

Closes #714.

This pull request primarily updates dependencies to their latest major versions and refactors React imports throughout the codebase to align with React 19 best practices. The changes focus on ensuring compatibility with React 19, removing unnecessary default React imports, and updating related packages.

Dependency upgrades and compatibility:

• Updated major dependencies to support React 19, including react, react-dom, @types/react, @types/react-dom, next, next-mdx-remote, rehype-*, remark-*, unified, and uuid in package.json. This ensures the project is compatible with the latest ecosystem versions. [1] [2] [3]
• Upgraded development dependencies such as @next/eslint-plugin-next, eslint-config-next, and eslint-plugin-react-hooks to their latest versions for improved linting and compatibility.

React import refactor:

• Replaced default import React from "react" with named imports (JSX, createElement, forwardRef, etc.) in all component files to follow the new React 19 convention, which no longer requires a default React import for JSX. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19]
• Updated usages of React.createElement to use the direct createElement import, further aligning with React 19 best practices.

These changes collectively modernize the codebase, improve maintainability, and prepare the project for future development with the latest React ecosystem.

[Copilot]

Pull request overview

This PR modernizes the codebase by upgrading to React 19, Next.js 15, and related ecosystem packages, while refactoring all React imports to align with React 19's new JSX transform that no longer requires a default React import. The changes ensure compatibility with the latest React ecosystem and follow modern best practices.

Key changes include:

• Upgraded core dependencies (React 19, Next.js 15, rehype/remark packages, uuid 13)
• Replaced import React from "react" with named imports (JSX, createElement, forwardRef, etc.) across all components
• Updated Next.js Link usage from legacyBehavior pattern to the modern component prop pattern

Reviewed changes

Copilot reviewed 299 out of 421 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
package.json	Updated major versions of React (19.2.3), Next.js (15.5.9), TypeScript (5.9.3), and related ecosystem packages
src/components/common/Button/components/HelpIconButton/helpIconButton.tsx	Removed legacy Next.js Link wrapper, using component prop pattern
src/components/common/Button/components/CallToActionButton/callToActionButton.tsx	Removed legacy Next.js Link wrapper, using component prop pattern
src/components/Project/components/DataReleasePolicy/dataReleasePolicy.tsx	Updated external link to use MUI Link directly with proper attributes
src/components/Project/components/Contacts/contacts.tsx	Simplified email link rendering without legacy Link wrapper
src/components/Layout/components/Nav/nav.tsx	Updated navigation items to use component prop pattern
src/components/Export/components/ExportMethod/exportMethod.tsx	Simplified export button to use component prop pattern
src/components/Error/error.tsx	Updated homepage button to use component prop pattern
src/components/ComponentCreator/ComponentCreator.tsx	Changed from React.createElement to direct createElement import
src/components/MarkdownRenderer/markdownRenderer.tsx	Updated rehype-react configuration for React 19 JSX runtime
src/components/MarkdownRenderer/types.ts	Updated to use Components type from rehype-react v8
src/components/Table/hooks/UseVirtualization/types.ts	Fixed RefObject type to properly handle null
src/components/Filter/components/SearchAllFilters/searchAllFilters.tsx	Changed React.forwardRef to direct forwardRef import
All component files	Replaced import React from "react" with named imports (JSX, createElement, forwardRef, etc.)