docs: Add HuggingFace Space README for backend

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

README.space.md

@@ -0,0 +1,64 @@
+---
+title: AI Textbook Backend
+emoji: 🤖
+colorFrom: blue
+colorTo: green
+sdk: docker
+pinned: false
+license: mit
+---
+
+# AI-native Textbook Backend
+
+FastAPI backend with RAG (Retrieval-Augmented Generation) capabilities for the Physical AI & Humanoid Robotics textbook platform.
+
+## Features
+
+- **RAG Service**: OpenRouter-powered Q&A with Qdrant vector search
+- **ChatKit Integration**: OpenAI ChatKit SDK compatible endpoints
+- **Better-Auth Integration**: JWT authentication with Better-Auth service
+- **Translation API**: Dynamic Urdu translation
+- **Personalization**: User progress tracking and recommendations
+
+## Tech Stack
+
+- FastAPI 0.109.0
+- OpenAI SDK 1.12.0 (with OpenRouter)
+- Qdrant Client 1.7.0
+- PostgreSQL (Neon)
+- Better-Auth JWT
+
+## Environment Variables
+
+Required environment variables (set in Space Settings):
+
+```
+OPENAI_API_KEY=your_openrouter_api_key
+OPENAI_BASE_URL=https://openrouter.ai/api/v1
+QDRANT_URL=your_qdrant_url
+QDRANT_API_KEY=your_qdrant_api_key
+NEON_DB_URL=your_neon_db_connection_string
+SECRET_KEY=your_jwt_secret_key
+BETTER_AUTH_URL=https://your-auth-space.hf.space
+DEBUG=false
+LOG_LEVEL=info
+```
+
+## API Endpoints
+
+- `GET /` - Welcome message
+- `GET /health` - Health check
+- `POST /api/chatkit/chat` - ChatKit-compatible chat endpoint
+- `POST /api/chat` - Standard chat endpoint
+- `POST /api/auth/login` - User authentication
+- `POST /api/auth/register` - User registration
+- `GET /api/translation/translate` - Translation service
+- `POST /api/rag/search` - RAG search
+
+## Documentation
+
+Full API documentation available at: `/docs` (Swagger UI)
+
+## Repository
+
+https://github.com/NaveedTechLab/AI-native-textbook1