Adds ValidationTracker (agreement computation with 8s grace period),
validator health, peer quality, ledger economy, state tracking,
storage detail gauges, 7 synchronous counters, and agreement gauge.
29 new metrics covering validation agreement, peer quality, UNL health,
ledger economy, state tracking, and upgrade awareness.
Part of the external dashboard parity initiative across phases 2-11.
See docs/superpowers/specs/2026-03-30-external-dashboard-parity-design.md
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
