Fix mypy type errors for bind() return type narrowing

Add type ignore comments to resolve mypy errors where super().bind()
returns Runnable[..., BaseMessage] but chat models narrow to AIMessage.
These are safe ignores - the runtime types are correct.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: fede-kamel

libs/oci/langchain_oci/chat_models/oci_data_science.py

@@ -778,7 +778,7 @@ def bind_tools(
         formatted_tools = [convert_to_openai_tool(tool) for tool in tools]
         if tool_choice is not None:
             kwargs["tool_choice"] = tool_choice
-        return super().bind(tools=formatted_tools, **kwargs)
+        return super().bind(tools=formatted_tools, **kwargs)  # type: ignore[return-value]
 
 
 class ChatOCIModelDeploymentVLLM(ChatOCIModelDeployment):

libs/oci/langchain_oci/chat_models/oci_generative_ai.py

@@ -1285,7 +1285,7 @@ def bind_tools(
                 )
             kwargs["is_parallel_tool_calls"] = True
 
-        return super().bind(tools=formatted_tools, **kwargs)
+        return super().bind(tools=formatted_tools, **kwargs)  # type: ignore[return-value]
 
     def with_structured_output(
         self,
@@ -1358,7 +1358,7 @@ def with_structured_output(
                     key_name=tool_name, first_tool_only=True
                 )
         elif method == "json_mode":
-            llm = self.bind(response_format={"type": "JSON_OBJECT"})
+            llm = self.bind(response_format={"type": "JSON_OBJECT"})  # type: ignore[assignment]
             output_parser = (
                 PydanticOutputParser(pydantic_object=schema)
                 if is_pydantic_schema
@@ -1382,7 +1382,7 @@ def with_structured_output(
                 json_schema=response_json_schema
             )
 
-            llm = self.bind(response_format=response_format_obj)
+            llm = self.bind(response_format=response_format_obj)  # type: ignore[assignment]
             if is_pydantic_schema:
                 output_parser = PydanticOutputParser(pydantic_object=schema)
             else: