export declare function fetchMe(basePath?: string): Promise<{
    id: string;
    email?: string;
    [k: string]: unknown;
} | null>;
/** Sign in. Returns null on success, else an error message. */
export declare function loginWithAbstract(identifier: string, password: string, basePath?: string, usernameField?: string): Promise<string | null>;
/** Register. Returns null on success, else an error message. */
export declare function registerWithAbstract(identifier: string, password: string, basePath?: string, usernameField?: string): Promise<string | null>;
/** Sign out. Best-effort; never throws. */
export declare function logoutUser(basePath?: string): Promise<void>;
/** Change password (must be signed in). Returns null on success, else error. */
export declare function changePassword(currentPassword: string, newPassword: string, basePath?: string): Promise<string | null>;