/**
 * Flattens a nested object into a flat object with dot notation keys.
 *
 * @param obj - The object to flatten
 * @param prefix - Internal parameter for recursion (do not use)
 * @returns A flattened object with dot notation keys
 *
 * @example
 * ```ts
 * const nested = {
 *   user: {
 *     profile: {
 *       name: 'John',
 *       age: 30
 *     },
 *     settings: {
 *       theme: 'dark'
 *     }
 *   },
 *   app: {
 *     version: '1.0.0'
 *   }
 * };
 *
 * const flattened = flattenObject(nested);
 * // {
 * //   'user.profile.name': 'John',
 * //   'user.profile.age': 30,
 * //   'user.settings.theme': 'dark',
 * //   'app.version': '1.0.0'
 * // }
 * ```
 */
export declare function flattenObject(obj: Record<string, any>, prefix?: string): Record<string, any>;