Revert Vercel AI SDK adoption and implement clean abstraction for LLM providers

[bhouston]

Revert Vercel AI SDK adoption and implement clean abstraction for LLM providers

This PR implements issue #144 by removing the Vercel AI SDK and creating a clean abstraction for LLM providers.

Changes

1. Removed dependencies on Vercel AI SDK (ai and @ai-sdk/* packages)

2. Created a new LLM abstraction layer in packages/agent/src/core/llm/ with:

   • A message type system supporting system, user, assistant, and tool messages
   • A generic generateText() function that works with any provider
   • A provider interface that can be implemented for different LLM services
   • A provider factory system for creating provider instances

3. Implemented the Anthropic provider using the Anthropic SDK directly

4. Updated the toolAgentCore.ts and related files to use the new abstraction

5. Added support for the same functionality without relying on the Vercel AI SDK

Benefits

• More reliable LLM integration by using provider SDKs directly
• Cleaner abstraction between the application and specific LLM providers
• Easier to add support for other models in the future
• Better type safety with TypeScript interfaces for all components

Testing

The changes have been built and type-checked to ensure compatibility with the existing codebase.

Follow-up Tasks

As mentioned in the issue, these items will be addressed in separate PRs:

• Token caching
• Support for OpenAI, Ollama, and Grok/XAI

[github-actions]

🎉 This PR is included in version 0.7.0 🎉

The release is available on GitHub release

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[github-actions]

🎉 This PR is included in version mycoder-agent-v1.0.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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[github-actions]

🎉 This PR is included in version mycoder-v1.0.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀