Add comprehensive documentation for Claude Agent SDK including usage patterns, test examples, and development guide. Includes:
- CLAUDE.md with project structure and quick reference
- SDK test examples for query, client, and hooks
- Shared test utilities for auth and tmpdir management
- Detailed SDK overview and capabilities documentation
Add comprehensive documentation for the Claude Agent SDK, including:
- Overview and quickstart guide
- Installation and setup instructions
- Detailed feature descriptions (tools, hooks, subagents, etc.)
- Comparison with other Claude tools
- Branding guidelines and licensing information
