/**
 * Text-to-speech on the worker. Two engines:
 *   - "profile": OpenAI-compatible /v1/audio/speech using the worker's profile
 *     key (works if the gateway proxies TTS).
 *   - "edge": Microsoft Edge TTS — FREE, no key, runs on the worker's machine.
 *     The default, so口播 needs zero paid TTS.
 */
export interface WorkerLlmAudio {
    baseUrl: string;
    apiKey: string;
}
export declare function ttsProfile(llm: WorkerLlmAudio, text: string, voice: string | undefined, dest: string): Promise<void>;
/** Free Microsoft Edge TTS. Default voice is Chinese; override per job. */
export declare function ttsEdge(text: string, voice: string | undefined, dest: string): Promise<void>;
export declare function synthesize(engine: "profile" | "edge", llm: WorkerLlmAudio | undefined, text: string, voice: string | undefined, dest: string): Promise<void>;
