/** Clock display — sent as `x-time-format` to backend. */
export type AppTimeFormat = "24h" | "12h";
export declare const APP_TIME_FORMATS: readonly ["24h", "12h"];
export declare const APP_REQUEST_HEADER_TIME_FORMAT: "x-time-format";
/** date-fns pattern for time-only display. */
export declare function getTimePattern(timeFormat: AppTimeFormat): string;
export declare function isAppTimeFormat(value: string | null | undefined): value is AppTimeFormat;