docs: add disclaimer about cosine similarity

README.md

@@ -22,6 +22,10 @@ language:
 - Use **`pplx-embed-1`** for independent text embedding (queries, documents, semantic search)
 - Use **`pplx-embed-1-context`** for document chunks in RAG systems where surrounding context matters
 
+> [!IMPORTANT]
+> `pplx-embed-1` and `pplx-embed-1-context` natively produce *unnormalized* int8-quantized embeddings. Ensure that you compare them via *cosine similarity*.
+
+
 ![diag.png](assets/diag.png)
 
 ## Models