feat: initial commit — tcb_devportal Next.js app

Includes Helm chart (tcb-devportal), Jenkinsfile with homelab CI pipeline,
and Next.js app source.

src/app/[locale]/[...rest]/page.tsx

@@ -0,0 +1,5 @@
+import { notFound } from 'next/navigation'
+
+export default function CatchAllPage() {
+  notFound()
+}