Replaces the domain-based collect_snapshot with extract_all(), which iterates
all supported instruments via vw_dashboard.Dashboard. Each entry is stored as
{value, unit, str_state} grouped by component type. Units are validated against
a whitelist and normalised (d→days, °C→degC); unrecognised units are dropped.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>