/**
 * Render a fixed 20-character progress bar (`█████░░░░░`).
 *
 * - `total <= 0` returns all-empty (`░ × 20`); the caller is responsible for any N/A label.
 * - `current >= total` returns all-filled (`█ × 20`); never overflows.
 * - Intermediate states round to the nearest cell based on `current / total`.
 *
 * Pure function with no external state — shared across the CLI (import progress, file
 * upload progress, future progress events).
 */
export declare const renderProgressBar: (current: number, total: number) => string;