Fetch model and provider list from specified OpenRouter base URL

[chrarnoldus]

Kilo maintainer here. We received an issue that OpenRouter base url support is not fully implemented and @cobra91 graciously made a pull request. Be sure to credit him if this PR is accepted!

Summary of changes:

• Respect custom OpenRouter base url when fetching model and provider lists
• Bust the model list cache when the base url or api key changes
• Remove ineffective caching in a file
• Make connect-src CSP more lenient to allow fetching of the provider list in the webview

While I do think these changes are an improvement, there is still room for improvement, e.g.:

• There are still a few places where openrouter.ai is hardcoded
• Fetching the provider list in the webview will fail if the CORS policy doesn't allow it (doing it in the core would be better)
• Model list is only updated after saving
• Some other providers have similar issues

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Important

Enhance model and provider fetching by supporting custom OpenRouter base URLs, updating caching, API handling, and UI components.

• Behavior:
  • Fetch model and provider lists using a custom OpenRouter base URL in getOpenRouterModels() and getOpenRouterProvidersForModel().
  • Cache busting for model lists when base URL or API key changes in modelCache.ts.
  • Update webviewMessageHandler.ts to handle custom base URL and API key for OpenRouter.
• UI Components:
  • Add openRouterBaseUrl and openRouterApiKey to useRouterModels() and useSelectedModel() hooks.
  • Update ApiOptions.tsx and OpenRouter.tsx to include fields for custom base URL and API key.
• Misc:
  • Remove file-based caching in modelCache.ts.
  • Update Content Security Policy in ClineProvider.ts to allow fetching from any URL.
  • Adjust tests in ClineProvider.spec.ts and webviewMessageHandler.spec.ts to cover new functionality.

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[chrarnoldus]

This cache file seems to be ineffective, because it is only read after we just wrote it, so I decided to remove it.

[chrarnoldus]

options is a small object, see the type definition of GetModelsOptions

[daniel-lxs]

Hey @cte since you were the one who implemented the cache file for the models, do you think this is a good idea?