fix(vector store)!: fix file content API (#4105)

# What does this PR do?
- changed to match
https://app.stainless.com/api/spec/documented/openai/openapi.documented.yml

## Test Plan
updated test CI

src/llama_stack/apis/vector_io/vector_io.py

@@ -396,19 +396,19 @@ class VectorStoreListFilesResponse(BaseModel):
 
 
 @json_schema_type
-class VectorStoreFileContentsResponse(BaseModel):
-    """Response from retrieving the contents of a vector store file.
+class VectorStoreFileContentResponse(BaseModel):
+    """Represents the parsed content of a vector store file.
 
-    :param file_id: Unique identifier for the file
-    :param filename: Name of the file
-    :param attributes: Key-value attributes associated with the file
-    :param content: List of content items from the file
+    :param object: The object type, which is always `vector_store.file_content.page`
+    :param data: Parsed content of the file
+    :param has_more: Indicates if there are more content pages to fetch
+    :param next_page: The token for the next page, if any
     """
 
-    file_id: str
-    filename: str
-    attributes: dict[str, Any]
-    content: list[VectorStoreContent]
+    object: Literal["vector_store.file_content.page"] = "vector_store.file_content.page"
+    data: list[VectorStoreContent]
+    has_more: bool
+    next_page: str | None = None
 
 
 @json_schema_type
@@ -732,12 +732,12 @@ class VectorIO(Protocol):
         self,
         vector_store_id: str,
         file_id: str,
-    ) -> VectorStoreFileContentsResponse:
+    ) -> VectorStoreFileContentResponse:
         """Retrieves the contents of a vector store file.
 
         :param vector_store_id: The ID of the vector store containing the file to retrieve.
         :param file_id: The ID of the file to retrieve.
-        :returns: A list of InterleavedContent representing the file contents.
+        :returns: A VectorStoreFileContentResponse representing the file contents.
         """
         ...
 

src/llama_stack/core/routers/vector_io.py

@@ -24,7 +24,7 @@ from llama_stack.apis.vector_io import (
     VectorStoreChunkingStrategyStaticConfig,
     VectorStoreDeleteResponse,
     VectorStoreFileBatchObject,
-    VectorStoreFileContentsResponse,
+    VectorStoreFileContentResponse,
     VectorStoreFileDeleteResponse,
     VectorStoreFileObject,
     VectorStoreFilesListInBatchResponse,
@@ -338,7 +338,7 @@ class VectorIORouter(VectorIO):
         self,
         vector_store_id: str,
         file_id: str,
-    ) -> VectorStoreFileContentsResponse:
+    ) -> VectorStoreFileContentResponse:
         logger.debug(f"VectorIORouter.openai_retrieve_vector_store_file_contents: {vector_store_id}, {file_id}")
         provider = await self.routing_table.get_provider_impl(vector_store_id)
         return await provider.openai_retrieve_vector_store_file_contents(

src/llama_stack/core/routing_tables/vector_stores.py

@@ -15,7 +15,7 @@ from llama_stack.apis.vector_io.vector_io import (
     SearchRankingOptions,
     VectorStoreChunkingStrategy,
     VectorStoreDeleteResponse,
-    VectorStoreFileContentsResponse,
+    VectorStoreFileContentResponse,
     VectorStoreFileDeleteResponse,
     VectorStoreFileObject,
     VectorStoreFileStatus,
@@ -195,7 +195,7 @@ class VectorStoresRoutingTable(CommonRoutingTableImpl):
         self,
         vector_store_id: str,
         file_id: str,
-    ) -> VectorStoreFileContentsResponse:
+    ) -> VectorStoreFileContentResponse:
         await self.assert_action_allowed("read", "vector_store", vector_store_id)
         provider = await self.get_provider_impl(vector_store_id)
         return await provider.openai_retrieve_vector_store_file_contents(

src/llama_stack/providers/utils/memory/openai_vector_store_mixin.py

@@ -30,7 +30,7 @@ from llama_stack.apis.vector_io import (
     VectorStoreContent,
     VectorStoreDeleteResponse,
     VectorStoreFileBatchObject,
-    VectorStoreFileContentsResponse,
+    VectorStoreFileContentResponse,
     VectorStoreFileCounts,
     VectorStoreFileDeleteResponse,
     VectorStoreFileLastError,
@@ -921,22 +921,21 @@ class OpenAIVectorStoreMixin(ABC):
         self,
         vector_store_id: str,
         file_id: str,
-    ) -> VectorStoreFileContentsResponse:
+    ) -> VectorStoreFileContentResponse:
         """Retrieves the contents of a vector store file."""
         if vector_store_id not in self.openai_vector_stores:
             raise VectorStoreNotFoundError(vector_store_id)
 
-        file_info = await self._load_openai_vector_store_file(vector_store_id, file_id)
         dict_chunks = await self._load_openai_vector_store_file_contents(vector_store_id, file_id)
         chunks = [Chunk.model_validate(c) for c in dict_chunks]
         content = []
         for chunk in chunks:
             content.extend(self._chunk_to_vector_store_content(chunk))
-        return VectorStoreFileContentsResponse(
-            file_id=file_id,
-            filename=file_info.get("filename", ""),
-            attributes=file_info.get("attributes", {}),
-            content=content,
+        return VectorStoreFileContentResponse(
+            object="vector_store.file_content.page",
+            data=content,
+            has_more=False,
+            next_page=None,
         )
 
     async def openai_update_vector_store_file(