fix: Delete non-core code in test and README_cot documentation, leaving only the most basic code

examples/cot_agent_example.py

@@ -1,33 +0,0 @@
-#!/usr/bin/env python3
-"""
-CoT Agent Example - Demonstrates how to use Chain of Thought mode for reasoning
-"""
-
-import asyncio
-import sys
-from pathlib import Path
-
-# Add project root directory to path
-sys.path.append(str(Path(__file__).resolve().parent.parent))
-
-from app.agent import CoTAgent
-from app.logger import logger
-
-
-async def main():
-    # Create CoT agent
-    agent = CoTAgent()
-
-    # Provide a problem that requires thinking
-    question = "How do you put an elephant into a refrigerator?"
-
-    logger.info(f"Question: {question}")
-
-    # Run the agent and get results
-    result = await agent.run(question)
-
-    logger.info(f"Execution complete!")
-
-
-if __name__ == "__main__":
-    asyncio.run(main())