fix: Restore all files lost during destructive rebase

A previous `git pull --rebase origin main` dropped 177 local commits,
losing 3400+ files across admin-v2, backend, studio-v2, website,
klausur-service, and many other services. The partial restore attempt
(660295e2) only recovered some files.

This commit restores all missing files from pre-rebase ref 98933f5e
while preserving post-rebase additions (night-scheduler, night-mode UI,
NightModeWidget dashboard integration).

Restored features include:
- AI Module Sidebar (FAB), OCR Labeling, OCR Compare
- GPU Dashboard, RAG Pipeline, Magic Help
- Klausur-Korrektur (8 files), Abitur-Archiv (5+ files)
- Companion, Zeugnisse-Crawler, Screen Flow
- Full backend, studio-v2, website, klausur-service
- All compliance SDKs, agent-core, voice-service
- CI/CD configs, documentation, scripts

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

website/app/page.tsx

@@ -0,0 +1,17 @@
+import Header from '@/components/Header'
+import Footer from '@/components/Footer'
+import LandingContent from '@/components/LandingContent'
+import { getContent } from '@/lib/content'
+
+export default function Home() {
+  // Server-side: Lade Content aus Datei
+  const content = getContent()
+
+  return (
+    <main className="min-h-screen bg-white">
+      <Header />
+      <LandingContent content={content} />
+      <Footer />
+    </main>
+  )
+}