feat: BreakPilot PWA - Full codebase (clean push without large binaries)

All services: admin-v2, studio-v2, website, ai-compliance-sdk,
consent-service, klausur-service, voice-service, and infrastructure.
Large PDFs and compiled binaries excluded via .gitignore.

backend/frontend/preview.py

@@ -0,0 +1,27 @@
+from fastapi import APIRouter
+from fastapi.responses import FileResponse
+
+from .paths import EINGANG_DIR, BEREINIGT_DIR
+
+router = APIRouter()
+
+
+@router.get("/preview-file/{filename}")
+def preview_file(filename: str):
+    path = EINGANG_DIR / filename
+    if not path.exists():
+        return {"error": "Datei nicht gefunden"}
+    if path.suffix.lower() not in {".jpg", ".jpeg", ".png"}:
+        return {"error": "Vorschau nur für JPG/PNG möglich"}
+    return FileResponse(str(path))
+
+
+@router.get("/preview-clean-file/{filename}")
+def preview_clean_file(filename: str):
+    path = BEREINIGT_DIR / filename
+    if not path.exists():
+        return {"error": "Datei nicht gefunden"}
+    if path.suffix.lower() not in {".jpg", ".jpeg", ".png"}:
+        return {"error": "Vorschau nur für JPG/PNG möglich"}
+    return FileResponse(str(path))
+