/**
 * Startup data sync orchestration.
 *
 * Owns retry/backoff scheduling, single-flight locking, and the cache-clear
 * cascade triggered when sync writes new data. Mirrors the design of
 * PRTS-MCP's `ts/src/startupSync.ts`, simplified to a single dataset
 * (GameData tables) for now. New datasets (story, audio) plug in by adding
 * another `syncDataset` block — the orchestration scaffolding is reusable.
 *
 * Contract:
 * - Runs in a background task launched from `server.ts` before listen().
 * - Skips sync when `EF_DATA_PATH` is explicitly set (user manages their
 *   own data; we must not overwrite it).
 * - Each dataset syncs under a single-flight lock so overlapping retries
 *   share a mutex.
 * - Retries with exponential backoff (30s / 120s / 600s) when network is
 *   unavailable, then gives up until next process start.
 * - Clears data-layer caches when a sync writes new data so stale reads
 *   don't leak.
 */
export declare function runStartupSync(): Promise<void>;