Next.js 16, React 19.2, Identities page, Invitations identities step, PNPM Catalogs (#381)

* Upgraded to Next.js 16
* Refactored code to comply with React 19.2 ESLint rules
* Refactored some useEffect usages with the new useEffectEvent
* Added Identities page and added second step to set up an identity after accepting an invitation
* Updated all dependencies
* Introduced PNPM catalogs for some frequently updated dependencies
* Bugs fixing and improvements

packages/ui/src/makerkit/multi-step-form.tsx

@@ -386,6 +386,7 @@ function AnimatedStep({
 
   useEffect(() => {
     if (isActive) {
+      // eslint-disable-next-line react-hooks/set-state-in-effect
       setShouldRender(true);
     } else {
       const timer = setTimeout(() => setShouldRender(false), 300);