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>

klausur-service/frontend/src/main.tsx

@@ -0,0 +1,19 @@
+import React from 'react'
+import ReactDOM from 'react-dom/client'
+import App from './App'
+import './styles/global.css'
+
+// Listen for auth token from parent Studio window
+window.addEventListener('message', (event) => {
+  const data = event.data as { type?: string; token?: string }
+  if (data?.type === 'AUTH_TOKEN' && data?.token) {
+    localStorage.setItem('auth_token', data.token)
+    console.log('Auth token received from Studio')
+  }
+})
+
+ReactDOM.createRoot(document.getElementById('root')!).render(
+  <React.StrictMode>
+    <App />
+  </React.StrictMode>,
+)