Add App response type

[zacksmash]

A new Response method has been added called app(), to be used in Resource primitives for returning the required data to a ChatGPT app. An Enum has been added as well to assist with setting common OpenAI Apps SDK related values.

Example:

class WeatherAppResource extends Resource
{
    const TEMPLATE = 'ui://apps/weather';
    
    protected string $uri = self::TEMPLATE;

    protected string $mimeType = OpenAI::MIME_TYPE->value;

    // ...

    /**
     * Handle the resource request.
     */
    public function handle(): Response
    {
        return Response::app(view('mcp.app'),
            fn (App $app) => $app->prefersBorder()
        );
    }

Tip

$app includes some helpers for ChatGPT apps, but also includes a meta() method to allow adding additional items to the metadata response

This relies on #102, as you'll need to use the meta() and structuredContent() methods, on the Tool Response. meta() is used to load data into your app that is not seen by the Model/LLM. structuredContent() is used to hydrate your app with data, and provide the Model/LLM with contextual information about the state of the app. Docs Reference

#[IsReadOnly()]
class WeatherTool extends Tool
{

    ...

    /**
     * Handle the tool request.
     */
    public function handle(Request $request, WeatherData $weatherData): Response|array
    {
        $city = $request->get('city', 'San Francisco');

        $content = $weatherData->handle($request);

        return [
            Response::json($content), // Required for backwards compatibility with MCP
            Response::text("Here is the current weather information you requested for {$city}.")
                ->meta(['route' => 'weather'])
                ->structuredContent($content),
        ];
    }
}

This also relies on #101, as you'll need to use the $meta property in the Tool Definition to add additional required data for ChatGPT Apps:

#[IsReadOnly()]
class WeatherTool extends Tool
{

    ...

    /**
     * Get the tool's meta information.
     *
     * @return array<string, mixed>
     */
    public function meta(): array
    {
        return [
            OpenAI::OUTPUT_TEMPLATE->value => WeatherAppResource::TEMPLATE,
            OpenAI::TOOL_INVOKING->value => 'Working on it...',
            OpenAI::TOOL_INVOKED->value => 'Weather Tool Completed',
        ];
    }
}

Ref #99

[zacksmash]

There might be a better way to handle this, for ChatGPT Apps and MCP-UI. I'll tinker and come back to this.