export declare function formatEnvelopeTimestamp(timezone?: string, now?: Date): string;
export declare function prependEnvelopeTimestamp(content: string, timezone?: string): string;
/**
 * Remove a single leading envelope timestamp prefix from inbound text (session auto-title, etc.).
 * Does not strip arbitrary `[…]` — only the date+time-shaped prefix from {@link formatEnvelopeTimestamp}.
 */
export declare function stripEnvelopeTimestampPrefix(text: string): string;