State and metrics API

FGraffityARState exposes Status, Sequence, bLocalized, PlaceId, SectionId and LastError. FGraffityARCapabilities reports platform/provider/world-tracking/config/native-frame/readiness, permission, engine status and tracking. Capture metrics report admitted/completed/dropped/cancelled images, dimensions/bytes and timings. Runtime metrics report attempt/recall state, first-admitted-frame timing and retained candidate/opaque-state bytes; these are not total process memory.