feat: AI聊天室多Agent协作讨论平台

- 实现Agent管理，支持AI辅助生成系统提示词
- 支持多个AI提供商（OpenRouter、智谱、MiniMax等）
- 实现聊天室和讨论引擎
- WebSocket实时消息推送
- 前端使用React + Ant Design
- 后端使用FastAPI + MongoDB

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

backend/requirements.txt

@@ -0,0 +1,42 @@
+# FastAPI and server
+fastapi==0.109.0
+uvicorn[standard]==0.27.0
+python-multipart==0.0.6
+websockets==12.0
+
+# MongoDB
+motor==3.3.2
+pymongo==4.6.1
+beanie==1.25.0
+
+# HTTP client
+httpx==0.26.0
+aiohttp==3.9.1
+
+# AI SDK clients
+openai==1.12.0
+google-generativeai==0.3.2
+zhipuai==2.0.1
+
+# Data validation
+pydantic==2.6.0
+pydantic-settings==2.1.0
+
+# Security
+cryptography==42.0.2
+python-jose[cryptography]==3.3.0
+passlib[bcrypt]==1.7.4
+
+# Utilities
+python-dotenv==1.0.1
+tenacity==8.2.3
+numpy==1.26.4
+
+# For embeddings and vector search
+sentence-transformers==2.3.1
+
+# Rate limiting
+slowapi==0.1.9
+
+# Logging
+loguru==0.7.2