feat: Implement Pinecone vector store integration

- Update config.py with Pinecone settings and model configurations
- Implement VectorStore class with Pinecone backend
- Add comprehensive vector operations (add, search, delete)
- Set up proper error handling and metadata management
- Add .gitignore for Python project

backend/requirements.txt

@@ -0,0 +1,12 @@
+fastapi==0.104.1
+uvicorn==0.24.0
+cohere==4.37
+faiss-cpu==1.7.4
+python-dotenv==1.0.0
+pydantic==2.4.2
+numpy==1.24.3
+transformers==4.35.2
+torch==2.1.1
+python-multipart==0.0.6 
+PyPDF2==3.0.1
+pycryptodome==3.17.1