@callback dimensions() :: pos_integer()

Returns the dimensionality of the embeddings generated by this adapter.

@callback embed(text :: String.t()) :: {:ok, [float()]} | {:error, term()}

Generates an embedding vector for the given text.

Returns {:ok, embedding} where embedding is a list of floats, or {:error, reason} if embedding generation fails.

@callback embed_batch(texts :: [String.t()]) :: {:ok, [[float()]]} | {:error, term()}

Generates embeddings for multiple texts in a batch.

This can be more efficient than calling embed/1 multiple times. Returns {:ok, embeddings} where embeddings is a list of lists of floats, or {:error, reason} if embedding generation fails.