/**
 * Return a locale's AM/PM (day-period) labels as `[AM-label, PM-label]`.
 *
 * - Labels are locale-varying: `en-US` → `["AM", "PM"]`, `en-GB` →
 *   `["am", "pm"]`, `sv-SE` → `["fm", "em"]`, `zh-CN` → `["上午", "下午"]`,
 *   `ar-SA` → `["ص", "م"]`.
 * - Uses the host runtime's `Intl` data via `Intl.DateTimeFormat`, so output
 *   depends on the runtime's ICU build.
 * - Returns `[]` if `locale` is not a valid BCP 47 tag.
 *
 * @param locale BCP 47 locale tag (e.g. "en-US", "fr-FR", "ar-SA")
 * @returns 2-element `[AM-label, PM-label]` array, or `[]` on invalid input
 *
 * @example getLocaleMeridiems("en-US") // ["AM", "PM"]
 * @example getLocaleMeridiems("en-GB") // ["am", "pm"]
 * @example getLocaleMeridiems("zh-CN") // ["上午", "下午"]
 * @example getLocaleMeridiems("not-a-locale") // []
 */
export declare function getLocaleMeridiems(locale: string): string[];