Add LLM error alert functionality to display specific error messages based on API responses. Introduce new LlmErrorAlertType interface for structured error alerts. Update chat components to manage and display LLM error alerts effectively, improving user feedback during error scenarios.
* Use backend API route to fetch dynamic models
# Conflicts:
# app/components/chat/BaseChat.tsx
* Override ApiKeys if provided in frontend
* Remove obsolete artifact
* Transport api keys from client to server in header
* Cache static provider information
* Restore reading provider settings from cookie
* Reload only a single provider on api key change
* Transport apiKeys and providerSettings via cookies.
While doing this, introduce a simple helper function for cookies
