{"message":"Why API - Children's Question Answering Service","version":"0.0.2","build":2,"endpoints":{"POST /answer":"Answer a child's question with text and image","POST /text-to-speech":"Generate TTS once per card (then save MP3 via save-to-shelf); do not call when playing shelf","POST /save-to-shelf":"Save card (text, image, audio) to Wissensregal (API key required)","GET /shelf":"Retrieve shelf entries for a guest with pagination and signed URLs (API key required)","DELETE /shelf/{item_id}":"Delete a shelf item (API key + X-Guest-Id required; only own items)","PATCH /shelf/{item_id}":"Update answer quality rating 1/0/-1 (API key + X-Guest-Id required; only own items)"}}