/**
 * Tokyo Night rainbow gradient for the Zoe Agent logo. Pure, deterministic, no
 * dependency. Each cell at (row, col) within a (rows × cols) grid is projected
 * onto the 45° axis: `t = (col + row) / ((cols-1) + (rows-1))` — sweeps
 * bottom-left → top-right; for a single row it reduces to a horizontal sweep.
 *
 * Interpolation is RGB between ADJACENT palette stops (red→orange→yellow→green
 * →cyan→blue→purple). Adjacent rainbow hues lerp cleanly (no muddy mid-tones),
 * and since the stops ARE the Tokyo Night accents, the result stays on-palette.
 */
export declare function rainbowCellColor(row: number, col: number, rows: number, cols: number, stops: readonly string[]): string;