Make Gemini provider part of AI Recipe

I'll do it myself.

Assigning to AI lead for initial sign-off.

This also needs approval from @pameeela (product owner), since it does add a dependency, which introduces a certain amount of risk for us, and she needs to decide if this feature is necessary for Drupal CMS, or if it's better to just ask people to add it to their sites on their own.

Could you run a test of how well Gemini works with the Drupal CMS Assistant.

https://docs.google.com/spreadsheets/d/1zzqJTxCboYPTnpA33Kt1cDg7gQzPh2g3...

Could take a copy of this spreadsheet and run it manually for Gemini. I still don't know the process for deciding which providers are included.

Moving to Needs work for the comments in #6.

Also, note the forthcoming language and format for the API key in ✨ Clearer instructions during the AI Installer Active .

I would be opposed to adding a third provider within the existing recipe, since we already have the problem that it currently installs two modules but only uses one. This would make it three modules, only using one. Obviously, this is not scalable as other providers become viable.

Seems like we will eventually want to swap it around so you choose the provider first, and that applies the appropriate recipe with only the one module needed. Unless we instead opt to promote a single provider?

@yautja_cetanu - Thank you for the list of test cases. I was thinking for asking something like this. We can try to make to automate this e2e tests for other providers later. I will work on this.

@pameeela – I understand your perspective. I believe this requires further discussion to determine the best approach. From an end-user standpoint, when downloading and installing Drupal CMS, enabling AI, and finding only two major providers (OpenAI and Anthropic) while Google's Gemini is absent, it may be difficult to justify.

I also agree that there should be clear principles guiding provider selection, as including all available providers may not be feasible. However, given that OpenAI and Anthropic are included, it seems reasonable to consider Gemini as well—especially since many agencies partner with GCP and are likely to use Gemini as their primary LLM provider.

For now, I’ll continue working on this PR, ensuring all tests pass and addressing any necessary fixes while this decision is being discussed.

P.S. If the decision is to exclude Gemini from the default setup, I’m happy to create a separate recipe for it.

We've been exploring an automated test framework here: https://www.drupal.org/project/ai_test_ui →
This tests just the agents bit of it and then we'd need another thing for testing Assistant prompts with chat history connected to the agents.