AAGT Core - AI Agent for Trading

Core types, traits, and abstractions for the AAGT framework.

This crate provides:

• Agent system (agent) - AI agent with tool calling
• Tool definitions (tool) - Define callable tools
• Message types (message) - Conversation messages
• Streaming (streaming) - Stream response handling
• Memory (memory) - Short and long-term memory
• Strategy (strategy) - Automated trading pipelines
• Risk control (risk) - Trading safeguards
• Simulation (simulation) - Trade simulation
• Multi-agent (multi_agent) - Agent coordination