Centralized EKÁER configuration in new EkaerSettings class (company info, EUR-HUF rate, thresholds). Refactored service and mapper to use EkaerSettings. Added EkaerValueCalculator for HUF value logic. Extended EkaerHistory with ConversionRate for audit. Added IsEkaer to Partner. Updated mapping, VTSZ normalization, UI grid, CSS, and tests. Added diagnostic commands to settings.local.json.
