Update everything to use google-genai SDK

[markmcd]

Description of the feature request:

Lots of notebooks are using the google-generativeai SDK, but now that google-genai is at 1.0, we should be using that.

e.g. pip install google-generativeai needs to be replaced with pip install google-genai and then relevant code and text needs to be updated.

There's lots to do right now, but we can do every notebook independently so this would be a great one to open to community contributions. If you want to work on one, check the open PR list to see if someone has already done it, then just send a PR directly (but stick to one notebook per PR).

And here's the migration guide: https://ai.google.dev/gemini-api/docs/migrate

[mitrick2]

Are there plans to create a google-genai SDK for JS?