/**
 * Synchronously refresh the usage cache when the active account is on
 * the verge of needing auto-engage. Returns silently on every failure
 * mode (no token, network down, rate-limited): the existing
 * cache-based path takes over and behaviour is identical to before.
 *
 * Gated behind a precise predicate so we don't pay the round-trip on
 * the 99% of invocations where the cache is fresh OR fallback is
 * already on OR there's no key to engage anyway.
 */
export declare function preWarmUsageForAutoEngage(claudeJsonPath: string, accountsDirPath: string): Promise<void>;