/**
 * localStorage that tolerates not being there.
 *
 * `typeof window !== "undefined"` was the guard these call sites used, and it
 * answers the wrong question: it says "am I in a browser", not "can I read
 * storage". Three things make that distinction real rather than theoretical:
 *
 * - A browser can have storage **disabled**. Safari in private mode, a blocked
 *   third-party cookie policy, and a sandboxed iframe all give you a `window`
 *   whose `localStorage` property *throws on access* — a SecurityError raised
 *   before any method is called, which no amount of null-checking the result
 *   catches.
 * - A test environment can be **half torn down**. jsdom is disposed at the end
 *   of a file while React is still finishing a concurrent render, so `window`
 *   survives as a husk and `localStorage.getItem` is no longer a function.
 *   That is how this was found: `TypeError: localStorage.getItem is not a
 *   function`, thrown out of a render, failing a suite in which every one of
 *   709 tests passed.
 * - Server rendering has no `window` at all, which is the only case the old
 *   guard actually covered.
 *
 * Reading a UI preference is never worth a crash. Every function here fails to
 * `null` / no-op, so a user with storage switched off gets the default
 * appearance instead of a blank page.
 */
/** The stored string for `key`, or null if it is unset or unreadable. */
export declare function readStoredString(key: string): string | null;
/** Persist `value` under `key`. A no-op when storage is unavailable. */
export declare function writeStoredString(key: string, value: string): void;
/** Remove `key`. A no-op when storage is unavailable. */
export declare function removeStoredString(key: string): void;