💾 Storage Convention

Capability	Recommended Storage	Content
ref.save()	File system	Full-res PNG path
ref.session()	MMKV / AsyncStorage	JSON metadata (URLs, paint records, brush color, etc.)

MaskSegmentSession Structure

{
  version: 1;
  originUrl: string;
  maskUrl: string;
  painted: PaintedRegionRecord[];  // { regionId, regionName, color, configJson? }
  paintHistory: number[];
  currentColor?: BgrColor;
  currentColorConfigJson?: Record<string, unknown>;
  savedAt: number;
}