feat: expose Gemini grounding metadata

[valtzu]

Example:

$ php examples/google/grounding.php
Symfony is an open-source PHP framework designed to accelerate the creation and maintenance of web applications. It provides a set of reusable PHP components and bundles that simplify complex development tasks, allowing developers to build robust and scalable applications. By promoting best practices and design patterns, Symfony gives developers full control over the application's configuration and customization.
Search queries: what is Symfony framework
Sources: wikipedia.org, ntchosting.com, symfony.com, drupalize.me

Up for discussion if it'd be better to do some extra processing (to provide a stable data structure for the user of this library) for the data or it's ok to expose as-is.

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Also worth noting that I see this information as something you want to save with your chat (basically within AssistantMessage), so in that sense I'm not 100% sure if this is the correct place for this.

[chr-hertel]

Great addition, was thinking if "grounding" is a vendor specific term - since you also used "sources" in the output. WDYT should we use a more general term like "sources" instead?

[chr-hertel]

That's quite straight forward to test, please add one

[chr-hertel]

@valtzu do you still want to work on this here or move it to symfony/ai?

[valtzu]

After some thinking, I'd prefer to have this logic in the model client / response converter instead of needing to wire an additional vendor-specific output processor.

Also I want to see if this can be done for streams too.

Closing here, may get back to this later in symfony/ai

Thanks