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/admin/rag/README.md

@@ -0,0 +1,59 @@
+# RAG Admin Page Refactoring
+
+## Status: Partially Refactored
+
+The large `page.tsx` (2,964 lines) has been partially split into smaller components.
+
+## Structure
+
+```
+website/app/admin/rag/
+├── page.tsx                    # Main page (needs update to import components)
+├── types.ts                    # Shared type definitions (150 lines)
+├── components/
+│   ├── index.ts                # Component exports
+│   ├── CollectionsTab.tsx      # Collections management (593 lines)
+│   ├── UploadTab.tsx           # File upload (327 lines)
+│   ├── IngestionTab.tsx        # Ingestion control (512 lines)
+│   └── DocumentsTab.tsx        # Document browser (425 lines)
+└── wizard/                     # Existing wizard subdirectory
+```
+
+## Extracted Components
+
+| Component | Lines | Description |
+|-----------|-------|-------------|
+| CollectionsTab | 593 | Collection CRUD, CollectionCard |
+| UploadTab | 327 | File upload with drag & drop |
+| IngestionTab | 512 | Ingestion control, progress, history |
+| DocumentsTab | 425 | Document list, filtering, preview |
+
+## Remaining in page.tsx
+
+- SearchTab (~230 lines)
+- MetricsTab (~110 lines)
+- SystemInfoTab (~350 lines)
+- Main component and tab navigation (~290 lines)
+
+## TODO
+
+1. Update `page.tsx` to import extracted components
+2. Extract remaining tabs (SearchTab, MetricsTab, SystemInfoTab)
+3. Add comprehensive tests
+
+## Types
+
+All shared types are in `types.ts`:
+- Collection, CreateCollectionData
+- IngestionStatus, SearchResult
+- UploadResult, LiveProgress
+- IndexedStats, PendingFile
+- IndexedDocument, DocumentContent
+- SystemInfo, TabId
+
+## Usage
+
+```tsx
+import { CollectionsTab, UploadTab, IngestionTab, DocumentsTab } from './components'
+import type { Collection, IngestionStatus } from './types'
+```