/**
 * Wraps fetch() and rewrites "fetch failed" errors to include the underlying
 * cause and a user-actionable diagnostic tip when possible. Non-network errors
 * and HTTP error responses (non-2xx) are not affected — the caller still
 * handles response.ok checks themselves.
 *
 * @param url The URL to fetch
 * @param init Standard fetch init options
 * @param context Optional short label (e.g. "token exchange") for the error message
 */
export declare function fetchWithDiagnostics(url: string, init?: any, context?: string): Promise<Response>;