- evcharger.cpp: phases() now calls meteredPhases() instead of returning PhaseNone
- smartchargingmanager: add chargerPhaseKey() with 3-level fallback
1. meteredPhases() when charger is active
2. effectivePhases from last known state
3. fallback 'A' + warning (previous behavior)
- Remove 4 FIXME comments on lines 394, 477, 517