This package wraps Go's stdlib `index/suffixarray` SA-IS implementation,
providing a `Sais16(text []uint16, textMax int, sa []int32, buf *[]int32)` API for
callers that need a caller-provided `[]int32` suffix array buffer. The `buf`
parameter is reusable scratch space that is grown as needed; callers should
preserve it across calls to amortize allocations.
