/**
 * Cell hash for jitter-v1 (ALGORITHM.md §20).
 *
 * Integer-only (§0) and expressed in operations a shader has too, so a GPU
 * backend can reproduce it exactly rather than approximate it. The row is
 * frame-global, not band-local, which is what keeps a band-split match
 * byte-identical to a whole-frame one.
 */
export declare function jitterHash(cx: number, cy: number, seed: number): number;