Add all required dependencies for backend

requirements.txt

@@ -1,23 +1,16 @@
-# --- Core backend ---
-fastapi==0.115.0
+fastapi==0.115.2
 uvicorn==0.29.0
 python-dotenv==1.0.1
-
-# --- LangChain stack ---
 langchain==0.1.16
 langchain-community==0.0.32
-langchain-groq==0.1.0
+langchain-groq==0.3.0
 sentence-transformers==2.2.2
 faiss-cpu==1.7.4
 tiktoken==0.7.0
 rank-bm25==0.2.2
-
-# --- Fix for sentence-transformers dependency ---
-huggingface-hub==0.24.6
-
-# --- PDF + text processing ---
-pypdf==3.17.1
-unstructured==0.10.30
-
-# --- Optional frontend for local tests ---
-gradio==5.49.1
+pypdf==4.2.0
+unstructured==0.14.5
+huggingface-hub==0.20.3
+gradio==5.49.1
+pandas==2.3.3
+numpy