Method cell_versions_for_coord

nodedb/src/engine/array/store/catalog.rs:404–441

Build a `(TileId, raw_bytes)` list for a specific `coord` across all versions (memtable + segments), ordered newest-first by `system_from_ms`.

(
        &self,
        hilbert_prefix: u64,
        coord: &[CoordValue],
        system_as_of: i64,
    )

    /// Build a `(TileId, raw_bytes)` list for a specific `coord` across all
    /// versions (memtable + segments), ordered newest-first by `system_from_ms`.
    fn cell_versions_for_coord(
        &self,
        hilbert_prefix: u64,
        coord: &[CoordValue],
        system_as_of: i64,
    ) -> Result<Vec<(TileId, Vec<u8>)>, nodedb_array::ArrayError> {
        let mut versions: Vec<(TileId, Vec<u8>)> = Vec::new();

        // Memtable (most recent writes, already newest-first from iter_tile_versions).
        for (tile_id, buf) in self
            .memtable
            .iter_tile_versions(hilbert_prefix, system_as_of)
        {
            if let Some(bytes) = buf.get_cell_bytes(coord) {
                versions.push((tile_id, bytes.to_vec()));
            }
        }

        // Segment versions — gather all qualifying versions across all segments,
        // then sort newest-first so memtable + segment ordering is correct.
        let mut seg_versions: Vec<(TileId, Vec<u8>)> = Vec::new();
        for h in self.segments.values() {
            let reader = h.reader();
            for item in reader.iter_tile_versions(hilbert_prefix, system_as_of)? {
                let (tile_id, tile_payload) = item?;
                if let TilePayload::Sparse(sparse) = &tile_payload
                    && let Some(bytes) = extract_cell_bytes(sparse, coord)?
                {
                    seg_versions.push((tile_id, bytes));
                }
            }
        }
        // Sort segment versions newest-first by system_from_ms.
        seg_versions.sort_by_key(|(a, _)| std::cmp::Reverse(a.system_from_ms));
        versions.extend(seg_versions);

        Ok(versions)
    }
}

fn parse_segment_seq(id: &str) -> Option<u64> {