/**
 * `sessionStorage` persistence for the auth-flow form values. Survives
 * back-button navigation between auth steps (PHONE_ENTRY → OTP → back)
 * so the user doesn't have to re-type their phone / email / name.
 *
 * Cleared on successful auth (the provider watches
 * `state.step === 'AUTHENTICATED'` and calls `clearAllFormState()`) and
 * automatically when the tab closes (sessionStorage default behaviour).
 *
 * OTP digits are deliberately NOT persisted — they're single-use and
 * time-sensitive, so the OTP page never wires this in.
 *
 * All functions are SSR-safe and silent on storage failures (private
 * browsing modes can throw on access; quota errors on write).
 */
/** Read a stored form snapshot. Returns null when missing or unparseable. */
export declare function readFormState<T>(key: string): T | null;
/** Persist a form snapshot. No-op on quota exceeded / disabled storage. */
export declare function writeFormState<T>(key: string, value: T): void;
/** Clear one form's snapshot. */
export declare function clearFormState(key: string): void;
/**
 * Wipe every kit-persisted form snapshot. Called on successful auth so
 * the next session starts from a clean slate (no stale phone/email
 * pre-filled into a fresh login).
 */
export declare function clearAllFormState(): void;
