docs: add Gemini style guide

[Maijin]

Vibecoded Style Guide draft for Gemini please take a look and see if there are anything else we want to remove/add here. This should improve the quality of the Gemini reviews. https://docs.cloud.google.com/gemini/docs/code-review/style-guide #3091

Checklist

• No CHANGELOG update needed

• No new tests needed

• No documentation update needed

• This submission includes AI-generated code and I have provided details in the description.

[gemini-code-assist]

Note

Gemini is unable to generate a review for this pull request due to the file types involved not being currently supported.

[williballenthin]

i tend to think most of the content should/is already enforced by linters, and Gemini can read the config if it wants to know more. therefore, maybe not a good use of tokens.

this guide also needs a small section on how to run the linters and tests (via pre-commit).

[Maijin]

@williballenthin

That's correct but unfortunately (unless I misread from the documentation) this is not possible through this bot.

We could add an instruction that if any of the linter issue is detected, it recommends the user to run the linters and where to find information - what do you think?

[williballenthin]

unfortunately (unless I misread from the documentation) this is not possible through this bot.

oh i see, this is for the Gemini code review GitHub bot, not Gemini CLI. sorry i misunderstood.

We could add an instruction that if any of the linter issue is detected, it recommends the user to run the linters and where to find information - what do you think?

the linters should already be run by GHA, so i don't think Gemini needs to repeat those results.

in the past, i've found these LLM-based reviewers reasonably good at finding copy-paste errors, typos, weird constructs, etc. So maybe we can focus Gemini on those class of problems?

we might also be able to ask it to look at the git blame history for changed regions, to get a better context and highlight broken assumptions or changes.

[williballenthin]

do we even want to add this if the Bot is going away?

[mr-tz]

Yeah this is going away soon but eventually a new solution should become available. Maybe we revisit it then?