feat(api)!: support extra_body to embeddings and vector_stores APIs (#3794)

Applies the same pattern from
https://github.com/llamastack/llama-stack/pull/3777 to embeddings and
vector_stores.create() endpoints.

This should _not_ be a breaking change since (a) our tests were already
using the `extra_body` parameter when passing in to the backend (b) but
the backend probably wasn't extracting the parameters correctly. This PR
will fix that.

Updated APIs: `openai_embeddings(), openai_create_vector_store(),
openai_create_vector_store_file_batch()`

llama_stack/apis/vector_io/vector_io.py

@@ -11,6 +11,7 @@
 import uuid
 from typing import Annotated, Any, Literal, Protocol, runtime_checkable
 
+from fastapi import Body
 from pydantic import BaseModel, Field
 
 from llama_stack.apis.inference import InterleavedContent
@@ -466,6 +467,40 @@ class VectorStoreFilesListInBatchResponse(BaseModel):
     has_more: bool = False
 
 
+# extra_body can be accessed via .model_extra
+@json_schema_type
+class OpenAICreateVectorStoreRequestWithExtraBody(BaseModel, extra="allow"):
+    """Request to create a vector store with extra_body support.
+
+    :param name: (Optional) A name for the vector store
+    :param file_ids: List of file IDs to include in the vector store
+    :param expires_after: (Optional) Expiration policy for the vector store
+    :param chunking_strategy: (Optional) Strategy for splitting files into chunks
+    :param metadata: Set of key-value pairs that can be attached to the vector store
+    """
+
+    name: str | None = None
+    file_ids: list[str] | None = None
+    expires_after: dict[str, Any] | None = None
+    chunking_strategy: dict[str, Any] | None = None
+    metadata: dict[str, Any] | None = None
+
+
+# extra_body can be accessed via .model_extra
+@json_schema_type
+class OpenAICreateVectorStoreFileBatchRequestWithExtraBody(BaseModel, extra="allow"):
+    """Request to create a vector store file batch with extra_body support.
+
+    :param file_ids: A list of File IDs that the vector store should use
+    :param attributes: (Optional) Key-value attributes to store with the files
+    :param chunking_strategy: (Optional) The chunking strategy used to chunk the file(s). Defaults to auto
+    """
+
+    file_ids: list[str]
+    attributes: dict[str, Any] | None = None
+    chunking_strategy: VectorStoreChunkingStrategy | None = None
+
+
 class VectorDBStore(Protocol):
     def get_vector_db(self, vector_db_id: str) -> VectorDB | None: ...
 
@@ -516,25 +551,11 @@ class VectorIO(Protocol):
     @webmethod(route="/vector_stores", method="POST", level=LLAMA_STACK_API_V1)
     async def openai_create_vector_store(
         self,
-        name: str | None = None,
-        file_ids: list[str] | None = None,
-        expires_after: dict[str, Any] | None = None,
-        chunking_strategy: dict[str, Any] | None = None,
-        metadata: dict[str, Any] | None = None,
-        embedding_model: str | None = None,
-        embedding_dimension: int | None = 384,
-        provider_id: str | None = None,
+        params: Annotated[OpenAICreateVectorStoreRequestWithExtraBody, Body(...)],
     ) -> VectorStoreObject:
         """Creates a vector store.
 
-        :param name: A name for the vector store.
-        :param file_ids: A list of File IDs that the vector store should use. Useful for tools like `file_search` that can access files.
-        :param expires_after: The expiration policy for a vector store.
-        :param chunking_strategy: The chunking strategy used to chunk the file(s). If not set, will use the `auto` strategy.
-        :param metadata: Set of 16 key-value pairs that can be attached to an object.
-        :param embedding_model: The embedding model to use for this vector store.
-        :param embedding_dimension: The dimension of the embedding vectors (default: 384).
-        :param provider_id: The ID of the provider to use for this vector store.
+        Generate an OpenAI-compatible vector store with the given parameters.
         :returns: A VectorStoreObject representing the created vector store.
         """
         ...
@@ -827,16 +848,12 @@ class VectorIO(Protocol):
     async def openai_create_vector_store_file_batch(
         self,
         vector_store_id: str,
-        file_ids: list[str],
-        attributes: dict[str, Any] | None = None,
-        chunking_strategy: VectorStoreChunkingStrategy | None = None,
+        params: Annotated[OpenAICreateVectorStoreFileBatchRequestWithExtraBody, Body(...)],
     ) -> VectorStoreFileBatchObject:
         """Create a vector store file batch.
 
+        Generate an OpenAI-compatible vector store file batch for the given vector store.
         :param vector_store_id: The ID of the vector store to create the file batch for.
-        :param file_ids: A list of File IDs that the vector store should use.
-        :param attributes: (Optional) Key-value attributes to store with the files.
-        :param chunking_strategy: (Optional) The chunking strategy used to chunk the file(s). Defaults to auto.
         :returns: A VectorStoreFileBatchObject representing the created file batch.
         """
         ...