Summary

• Add Effect wrappers for AI SDK's generateText, streamText, and tool functions to provide seamless integration with the Effect runtime
• Wrappers properly handle async operations, streaming, and Effects-based services
• Include comprehensive documentation with examples for basic usage, streaming, tools with Effect services, and error handling
• Add tests covering all three wrapper functions and various use cases

Test plan

• Tests in packages/effect/src/for/ai/index.test.ts cover:
  • Basic generateText functionality
  • generateText with onFinish callback
  • Basic streamText with streaming consumption
  • tool wrapper with Effect service integration
  • Error handling with AiError
• All examples in the documentation (packages/effect/docs/for/ai.md) are accurate and runnable
• Package dependencies are correctly added (@ai-sdk/core as peer and dev dependency)