Add configuration for GCA and draft coding style.

[gspencergoog]

Description

This configures Google Code Assist so that it can be more helpful in its reviews. I also limited its comments to six at a time so as not to overwhelm.

I added a draft STYLE_GUIDE.md that includes what I think basic coding style should be for python and typescript projects. This is so that GCA has something concrete to gauge against, and we can totally modify it in future: it's just a draft. It follows Google style for OSS projects.

I also updated the GEMINI.md to describe the current state of the repo.

Summary

This pull request enhances the project's development workflow and code quality by integrating automated review assistance and establishing clear, comprehensive coding standards. It introduces Google Code Assist for more effective feedback, provides a detailed CODING_STYLE.md for Python and TypeScript based on Google's guidelines, and updates the contribution process with a new PR template and a reference to the style guide.

Highlights

• Google Code Assist Configuration: Configured Google Code Assist (GCA) to provide more helpful reviews, with a limit of six comments per review to prevent overwhelming authors.
• Coding Style Guide Introduction: Added a new STYLE_GUIDE.md document outlining basic coding style guidelines for Python and TypeScript projects, adhering to Google's open-source style. This serves as a reference for GCA and future contributions.
• Pull Request Template Addition: Introduced a standard PULL_REQUEST_TEMPLATE.md to streamline the pull request creation process, including sections for description, issue linking, and a pre-launch checklist.
• Contribution Guide Update: Modified CONTRIBUTING.md to include a new section that references the newly added CODING_STYLE.md, guiding contributors to adhere to the established style standards.
• Repository State Documentation: Updated GEMINI.md to accurately describe the current state of the repository, reflecting the changes and additions made.