export interface NavPayloadCacheDeps {
    /** Fetch a page, resolving to its HTML or null when it shouldn't be reused. */
    fetchPage: (target: string) => Promise<string | null>;
    /** Injected so tests drive expiry without sleeping. */
    now: () => number;
    /** Long enough to cover hover-to-click, short enough that nobody reads a
     *  page rendered from data this old. */
    ttlMs?: number;
    /** Cap on retained payloads; the oldest is evicted first. Pages are whole
     *  HTML documents, so this bounds memory on a link-dense page. */
    max?: number;
}
export interface NavPayloadCache {
    /** Warm `target`, unless a fresh entry is already present or in flight. */
    prefetch(target: string): void;
    /** Hand over `target`'s payload, or null. Single-use: a prefetch
     *  accelerates the NEXT click, and holding it past that would serve
     *  navigations from an increasingly stale render. */
    take(target: string): Promise<string | null> | null;
    /** Drop everything — called when a navigation commits, since entries were
     *  rendered against the page the user just left. */
    clear(): void;
    /** Retained entry count (tests + diagnostics). */
    size(): number;
}
export declare function createNavPayloadCache(deps: NavPayloadCacheDeps): NavPayloadCache;