feat: Add Letta SDK support for Python agents

[Ash-Blanc]

Summary

Adds comprehensive support for the Letta SDK (Python) as a framework provider to the better-agents CLI tool.

Changes

• Created new framework provider directory src/providers/frameworks/letta-py/
• Added index.ts - Framework provider configuration with Letta framework metadata
• Added knowledge.ts - Framework documentation, best practices, and code examples
• Added mcp-config.ts - MCP server configuration for accessing Letta documentation
• Registered Letta SDK in the main frameworks index

What Letta SDK Enables

With Letta SDK support, developers can:

• Build stateful Python agents with persistent memory
• Use self-editing memory blocks for agent state management
• Integrate tools and external services
• Access comprehensive documentation through MCP integration

Implementation Details

Follows the same pattern as existing framework providers (Agno, Mastra, LangGraph) to ensure consistency and maintainability. The implementation provides coding assistants with the knowledge needed to guide developers through the Letta SDK best practices.

Related Documentation

• Letta Documentation
• Letta SDK Repository