Function array_vshard_for_tile 

pub fn array_vshard_for_tile(
    hilbert_prefix: u64,
    prefix_bits: u8,
) -> Result<u32>

Determine the primary owning vShard for a single tile identified by its raw Hilbert-prefix value.

hilbert_prefix — the tile’s u64 Hilbert key. prefix_bits — number of high-order bits used for routing (1–16).

Returns the vShard ID in [0, VSHARD_COUNT).