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/backend/routes/exams.py

@@ -0,0 +1,109 @@
+"""
+Klausur-Service Exam Routes
+
+CRUD endpoints for Klausuren.
+"""
+
+import uuid
+from datetime import datetime, timezone
+
+from fastapi import APIRouter, HTTPException, Request
+
+from models.exam import Klausur
+from models.requests import KlausurCreate, KlausurUpdate
+from services.auth_service import get_current_user
+import storage
+
+router = APIRouter()
+
+
+@router.get("/api/v1/klausuren")
+async def list_klausuren(request: Request):
+    """List all Klausuren for current teacher."""
+    user = get_current_user(request)
+    user_klausuren = [
+        k.to_dict() for k in storage.klausuren_db.values()
+        if k.teacher_id == user["user_id"]
+    ]
+    return user_klausuren
+
+
+@router.post("/api/v1/klausuren")
+async def create_klausur(data: KlausurCreate, request: Request):
+    """Create a new Klausur."""
+    user = get_current_user(request)
+
+    klausur = Klausur(
+        id=str(uuid.uuid4()),
+        title=data.title,
+        subject=data.subject,
+        modus=data.modus,
+        class_id=data.class_id,
+        year=data.year,
+        semester=data.semester,
+        erwartungshorizont=None,
+        students=[],
+        created_at=datetime.now(timezone.utc),
+        teacher_id=user["user_id"]
+    )
+
+    storage.klausuren_db[klausur.id] = klausur
+    return klausur.to_dict()
+
+
+@router.get("/api/v1/klausuren/{klausur_id}")
+async def get_klausur(klausur_id: str, request: Request):
+    """Get a specific Klausur."""
+    user = get_current_user(request)
+
+    if klausur_id not in storage.klausuren_db:
+        raise HTTPException(status_code=404, detail="Klausur not found")
+
+    klausur = storage.klausuren_db[klausur_id]
+    if klausur.teacher_id != user["user_id"] and user.get("role") != "admin":
+        raise HTTPException(status_code=403, detail="Access denied")
+
+    return klausur.to_dict()
+
+
+@router.put("/api/v1/klausuren/{klausur_id}")
+async def update_klausur(klausur_id: str, data: KlausurUpdate, request: Request):
+    """Update a Klausur."""
+    user = get_current_user(request)
+
+    if klausur_id not in storage.klausuren_db:
+        raise HTTPException(status_code=404, detail="Klausur not found")
+
+    klausur = storage.klausuren_db[klausur_id]
+    if klausur.teacher_id != user["user_id"] and user.get("role") != "admin":
+        raise HTTPException(status_code=403, detail="Access denied")
+
+    if data.title:
+        klausur.title = data.title
+    if data.subject:
+        klausur.subject = data.subject
+    if data.erwartungshorizont:
+        klausur.erwartungshorizont = data.erwartungshorizont
+
+    return klausur.to_dict()
+
+
+@router.delete("/api/v1/klausuren/{klausur_id}")
+async def delete_klausur(klausur_id: str, request: Request):
+    """Delete a Klausur and all associated student work."""
+    user = get_current_user(request)
+
+    if klausur_id not in storage.klausuren_db:
+        raise HTTPException(status_code=404, detail="Klausur not found")
+
+    klausur = storage.klausuren_db[klausur_id]
+    if klausur.teacher_id != user["user_id"] and user.get("role") != "admin":
+        raise HTTPException(status_code=403, detail="Access denied")
+
+    # Remove student records
+    for student in klausur.students:
+        if student.id in storage.students_db:
+            del storage.students_db[student.id]
+
+    del storage.klausuren_db[klausur_id]
+    return {"success": True}