Update command and setting embedding caches to use metis

[mjbvz]

The command and setting embedding indexes currently use text3small. We should be good to switch these over the use metis embeddings, which has better quality and a smaller size

This involves:

• Update our remote embedding caches for these to also publish metis embeddings
• Switch our code in copilot chat over to use metis. This should be as simple as replacing EmbeddingType.text3small_512 with EmbeddingType.metis_1024_I16_Binaryonce the ICombinedEmbeddingIndex has been updated to support metis

[mjbvz]

One other note: for best results when re-ranking embeddings, use the inputType option in the call to computeEmbeddings. The query should use inputType: "query", while the text you are searching should use inputType: "document"