New Features:
- ClaudeSDKError base exception for catch-all error handling (Python parity)
- Output.async/1 and Output.with_async_timeout/2 for async hook processing
- Tool.simple_schema/1 helper to reduce MCP tool schema boilerplate
- Transport.end_input/1 optional callback for signaling stdin EOF

Improvements:
- CLIStream tracks received_first_message? and received_result? for diagnostics
- Updated permissions_live.exs to use streaming mode for control protocol
- Updated sdk_mcp_tools_live.exs to use simple_schema helper
- Enhanced documentation for hooks, MCP tools, and error handling

Tests:
- Added comprehensive tests for ClaudeSDKError and all error types
- Added tests for Output.async/1 and Output.with_async_timeout/2
- Added tests for Tool.simple_schema/1 with various input formats
- Added tests for Transport.end_input/1 optional callback