Add Anthropic (Claude) as a model provider

[hannah-15]

Implement support for Anthropic API alongside the existing OpenAI provider:

• Add @anthropic-ai/sdk dependency
• Extend config schema with provider field ("openai" or "anthropic")
• Add Anthropic to MODEL_PROVIDERS list with default baseURL
• Update model wizard to capture and pass provider type
• Update CLI to branch on provider type and instantiate AnthropicModelProvider
  or OpenAIModelProvider accordingly

Implement AnthropicModelProvider with:

• Message conversion handling system prompts as separate parameter
• Tool conversion mapping to input_schema format
• Response parsing for text, thinking, and tool_use content blocks
• Thinking block signature preservation for multi-turn conversations
• Token usage normalization

[MagicCube]

Hi @hannah-15, thanks so much for your contribution. And YES! We love Anthropic!

However I just added a new *stream() method to the ModelProvider's interface this morning, as well as a new property named streaming?: boolean in the AssistantMessage interface. And I also found that there're also some lint issues in your PR need to be improved as well.

Please refer to a985f67

Would you please kindly implement the *stream() feature and fix all the linting/testing issues? Looking forward to your reply.

Thanks again!

[hannah-15]

Hi @MagicCube, thanks for the comment! I've just pushed an update that addresses both points.

1. stream() implementation for AnthropicModelProvider
2. All bun run check steps now pass cleanly (tsc --noEmit, eslint, and bun test)

Let me know if any further issue!

Hi @hannah-15, thanks so much for your contribution. And YES! We love Anthropic!

However I just added a new *stream() method to the ModelProvider's interface this morning, as well as a new property named streaming?: boolean in the AssistantMessage interface. And I also found that there're also some lint issues in your PR need to be improved as well.

Please refer to a985f67

Would you please kindly implement the *stream() feature and fix all the linting/testing issues? Looking forward to your reply.

Thanks again!

[hannah-15]

Hi @MagicCube, the check workflow needs your approval. Can you kindly trigger it when you review the code? Thanks!

[MagicCube]

Nice job, @hannah-15! It's a good start as your ver first PR on GitHub.

[hannah-15]

Thanks @MagicCube, it's my pleasure to make contribution!