The overload `tools` or `defaultTools` method in `ChatClientBuilder` causes FunctionToolCallback not taking effect.

Bug Desception

I have the following FunctionToolCallback instance created and registered to ChatClient Builder as below:

FunctionToolCallback toolCallback1 = ...
FunctionToolCallback toolCallback2 = ...
ChatClient.create(chatModel)
    .prompt("What's the weather like in Copenhagen?")
    .tools(toolCallback1, toolCallback2)
    .call()
    .content();

The above tool registration will not take effect because it actually calls the Builder defaultTools(Object... toolObjects); overload method instead of the Builder defaultTools(List<ToolCallback> toolCallbacks);.

Builder defaultTools(Object... toolObjects); method only works for Method tool, because inside ToolCallbacks.from(toolObjects) it only accepts Method tools:

@Override
public ChatClientRequestSpec tools(Object... toolObjects) {
	Assert.notNull(toolObjects, "toolObjects cannot be null");
	Assert.noNullElements(toolObjects, "toolObjects cannot contain null elements");
	this.functionCallbacks.addAll(Arrays.asList(ToolCallbacks.from(toolObjects))); // here only accepts Method tools
	return this;
}

Only the following form is correct:

ToolCallback toolCallback1 = ... // must be ToolCallback type but not FunctionToolCallback type.
ToolCallback toolCallback2 = ... // must be ToolCallback type but not FunctionToolCallback type.
ChatClient.create(chatModel)
    .prompt("What's the weather like in Copenhagen?")
    .tools(toolCallback1, toolCallback2)
    .call()
    .content();

It's very easy to make the above mistake. There's no compilation error because of the overload methods and it's not easy to debug and find the problem.

Environment

1.0.0-M6

Start with the ChatClientBuilder tools/defaultTools overloads and the ChatClientRequestSpec.tools(Object...) entry point shown in the report. Trace how ToolCallbacks.from(toolObjects) handles FunctionToolCallback, then add regression coverage showing that the reported registration form takes effect. Done means FunctionToolCallback registrations are handled as intended without the misleading overload behavior.