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>

backend/content_service/requirements.txt

@@ -0,0 +1,35 @@
+# BreakPilot Content Service Dependencies
+
+# FastAPI & Web Framework
+fastapi==0.109.0
+uvicorn[standard]==0.27.0
+python-multipart==0.0.6
+
+# Database
+sqlalchemy==2.0.25
+psycopg2-binary==2.9.9
+alembic==1.13.1
+
+# Storage
+minio==7.2.3
+
+# Validation
+pydantic==2.5.3
+email-validator==2.1.0
+
+# Matrix SDK (für Sprint 3-4)
+matrix-nio==0.24.0
+
+# Authentication (JWT)
+python-jose[cryptography]==3.3.0
+passlib[bcrypt]==1.7.4
+python-dotenv==1.0.0
+
+# HTTP Client
+httpx==0.26.0
+
+# Image Processing (für Thumbnails)
+pillow==10.2.0
+
+# Utils
+python-dateutil==2.8.2