feat(login): update to nextjs 16, improve caching, change default colors (#11629)

# Which Problems Are Solved

Updated the project to use the latest versions of Next.js and React, and
implemented a SWR caching strategy for key settings API calls to improve
performance. Adjusted configuration to ensure compatibility with Next.js
16.

# How the Problems Are Solved

- Updated next to 16.1.6, react & react-dom to 19.2.4, and next-intl to
4.8.3.
- Implemented `API_CACHE_ENABLED` and `API_CACHE_CONFIG` (replacing
deprecated unstable_cacheLife) for:
  - getBrandingSettings
  - getSecuritySettings
  - getPasswordComplexitySettings
  - getLoginSettings ...
- Updated default theme colors from blue to a more neutral black and
white

# Additional changes

- Updated login docker image to node 24

---------

Co-authored-by: Ramon <[email protected]>

apps/login/src/components/idp-process-handler.tsx

@@ -94,7 +94,7 @@ export function IdpProcessHandler({
   }, [provider, id, token, requestId, organization, link, sessionId, linkFingerprint, postErrorRedirectUrl, router, t]);
 
   return (
-    <div className="flex min-h-screen items-center justify-center">
+    <div className="flex items-center justify-center">
       {samlData && <AutoSubmitForm url={samlData.url} fields={samlData.fields} />}
       {loading && (
         <div className="flex flex-col items-center space-y-4">