Break the 88-line produce_system_status() into five focused helpers:
_get_agents_online(), _get_visitors(), _get_uptime_seconds(),
_get_thinking_active(), and _get_memory_count(). Main function becomes
a thin coordinator. Adds unit tests for each helper.
Fixes#1194
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>