fix: update import path for TextExplainer to reflect new structure

src/processors/pdf_text_extractor.py

@@ -2,7 +2,7 @@ import base64
 import os
 from typing import Optional, Tuple, List, Dict, Any
 from mistralai import Mistral
-from utils.text_explainer import TextExplainer
+from src.utils.text_explainer import TextExplainer
 
 class PDFTextExtractor:
     """PDF text extraction using Mistral AI OCR."""