Replace raw JSON dumps with concise, scannable log lines when
show_full_output is enabled. Adds an onMessage callback to the SDK
runner that formats each message type into 1-2 line summaries with
emoji prefixes, tool-specific parameter display, result correlation
for parallel tool calls, and subagent progress tracking.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
