fix: Change faiss-gpu to faiss-cpu in requirements

- Replace faiss-gpu>=1.7.4 with faiss-cpu>=1.7.2
- FAISS-GPU support remains in code with automatic CPU fallback
- CPU version is more compatible and doesn't require CUDA for FAISS

requirements.txt

@@ -19,8 +19,7 @@ tokenizers>=0.15.0
 sentence-transformers>=2.2.0
 
 # Vector Database & Search
-# Use faiss-gpu for GPU-accelerated vector search (falls back to CPU if GPU unavailable)
-faiss-gpu>=1.7.4
+faiss-cpu>=1.7.2
 numpy>=1.24.0
 scipy>=1.11.0