Scene-level header describing the external property value columns
(madi.property-columns.1). Every distinct value is stored once in
valueHeap as canonical compact JSON (UTF-8, keys sorted), sorted by
encoded byte sequence; valueOffsets holds distinctValueCount + 1 byte
offsets bracketing each distinct value; rows holds one u32 distinct-value
index per (bag, position) in row order; rowOffsets holds rowCount + 1
offsets (in value counts) bracketing each row inside rows.
Scene-level header describing the external property value columns (
madi.property-columns.1). Every distinct value is stored once invalueHeapas canonical compact JSON (UTF-8, keys sorted), sorted by encoded byte sequence;valueOffsetsholdsdistinctValueCount + 1byte offsets bracketing each distinct value;rowsholds one u32 distinct-value index per (bag, position) in row order;rowOffsetsholdsrowCount + 1offsets (in value counts) bracketing each row insiderows.