Refactor the OpenAI LLM implementation in the `openai-llm.ts` file.
- Update the model selection logic to support both 'gpt-4o' and 'o1-mini' models.
- Add conditional logic to handle different models and their respective prompts and options.
- Added OPENAI_API_KEY to the Env interface
- Added OPENAI_API_KEY to package.json dependencies
- Added @ai-sdk/openai to package.json dependencies
- Added Prompts interface to prompts-interface.ts
- Added Prompts implementation to anthropic-llm.ts and openai-llm.ts
- Added LLMType enum to llm-selector.ts
- Added selectLLM and getCurrentLLMType functions to llm-selector.ts
- Added AnthropicLLM and OpenAILLM classes to anthropic-llm.ts and openai-llm.ts
- Added getModel function to model.ts
- Added streamText function to stream-text.ts
- Updated chatAction function in api.chat.ts to use selectLLM and getCurrentLLMType
