feat: implement structured output with json schema

feat: add token usage and latency tracking for agent execution

feat: add multimodal input support for LLM agents

chore: rename package to gonostic

Merge pull request #1 from sultanfariz/claude/define-agent-types-exr4l

docs: complete README with executor, session agents, and provider docs

feat: add async task executor with worker pool

docs: document agent types in README

docs: add README with installation and core concepts

feat: add sequential, parallel, and pipeline workflow agents

feat: add LLM-powered reasoning agent

feat: add thread-safe MapState implementation

feat: add session-based agent types and invocation model

init: define core agent types and interfaces