Pin backend dependencies to compatible LangChain versions

requirements.txt

@@ -1,19 +1,19 @@
-fastapi
-uvicorn[standard]
-aiofiles
-python-multipart
-python-dotenv
-pandas
-PyPDF2
-pillow
-pytesseract
-chromadb
-langchain
-langchain-community
-langchain-core
-langchain-text-splitters
-langchain-groq
-groq
-sentence-transformers
-vosk
-pyttsx3
+fastapi==0.116.1
+uvicorn[standard]==0.37.0
+aiofiles==24.1.0
+python-multipart==0.0.20
+python-dotenv==1.1.1
+pandas==2.3.3
+PyPDF2==3.0.1
+pillow==11.3.0
+pytesseract==0.3.13
+chromadb==1.1.0
+langchain==0.3.27
+langchain-community==0.3.30
+langchain-core==0.3.76
+langchain-text-splitters==0.3.11
+langchain-groq==0.3.8
+groq==0.32.0
+sentence-transformers==5.1.1
+vosk==0.3.45
+pyttsx3==2.99