The Usage & Spend tab writes costHistoryDays/costHistoryMetric at runtime;
the General settings page snapshotted both on open, so applying any later
edit silently reverted the user's range or metric choice to the open-time
value. Both cfg_* properties now read persisted state live, the days field
pushes edits through valueModified (user-driven only, so an externally
driven rebind cannot echo back), and editing or restoring defaults still
breaks the binding like every other pending edit. Static pins require the
live reads and the shared outcome classifier.