/**
 * Builds the user style profile section injected into the system prompt.
 * Returns an empty string if the model has no meaningful data yet.
 */
export declare function buildUserStyleSection(): Promise<string>;
/**
 * Observes a user message to update the style model.
 * Fire-and-forget — never throws, never blocks the reply.
 */
export declare function observeUserMessage(message: string): void;