Adding Google API Suport

[01Rian]

This pull request introduces Google Gemini as a new AI provider in the "superdesign" extension, along with updates to support its integration across the codebase. The changes include adding configuration commands, extending the model selection interface, and enhancing backend functionality to handle the new provider. Below is a summary of the most important changes grouped by theme:

New AI Provider Integration:

• Added Google Gemini as a supported AI provider with model options (gemini-2.5-pro, gemini-2.5-flash, gemini-2.5-flash-lite) in src/providers/chatSidebarProvider.ts and src/webview/components/Chat/ModelSelector.tsx. [1] [2] [3]
• Implemented Google API key configuration command (superdesign.configureGoogleApiKey) in src/extension.ts and updated package.json to include the new command and settings. [1] [2] [3]

Backend Enhancements:

• Extended backend services (ChatMessageService, CustomAgentService) to support Google Gemini models, including API key validation, model selection, and error handling. [1] [2] [3] [4] [5]

Documentation Updates:

• Updated README.md to reflect support for Google Gemini and instructions for configuring API keys via the Command Palette.
• Added release notes for version 0.0.9 in CHANGELOG.md, documenting the addition of Google Gemini and related improvements.

These changes collectively enhance the extension's functionality by introducing a new AI provider and improving user experience with better configuration options and documentation.

[prometheas]

Would love to see this PR merged and shipped… 🙏🏼❤️

[hbmartin]

@01Rian I added these commits to my fork, hope you don't mind! (But if you do I'll remove it.)

https://github.com/hbmartin/secure-design/

[01Rian]

@hbmartin No problem, happy to help. It seems like superdesign is dead.

[hbmartin]

Fyi I'm considering whether to switch up model selection to make all the configuration steps more intuitive. It would be really great to get your vote / feedback here: hbmartin#43