imported `sentence_transformer` to CoordinatorAgent

src/agents/coordinator_agent.py

@@ -2,6 +2,7 @@ from typing import Dict, Any, Optional
 from .base_agent import BaseAgent
 import numpy as np
 from transformers import AutoTokenizer, AutoModel
+from sentence_transformers import SentenceTransformer
 import torch
 
 class CoordinatorAgent(BaseAgent):