adding google genai package https://github.com/googleapis/go-genai

[manishiitg]

PR Checklist

• Read the Contributing documentation.
• Read the Code of conduct documentation.
• Name your Pull Request title clearly, concisely, and prefixed with the name of the primarily affected package you changed according to Good commit messages (such as memory: add interfaces for X, Y or util: add whizzbang helpers).
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• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. Fixes #123).
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[manishiitg]

i @tmc can you check above

[jehiah]

@manishiitg it looks like there are a few minor lint errors to address.