prometheus-scrape.metrics_path was '/' which made prometheus-docker-sd scrape
the HTML root and fail with 'INVALID is not a valid start token', leaving the
targets up=0. Fixes per-container (cadvisor) + host (node_exporter) metrics so
they can be wired into the DRPC insights MCP for per-node resource attribution.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>