/**
 * Bounded ring buffer for console / network / error tails.
 * O(1) push, O(n) drain. Fixed capacity to keep page memory bounded.
 */
export declare class RingBuffer<T> {
    private readonly capacity;
    private items;
    constructor(capacity: number);
    push(item: T): void;
    tail(n: number): T[];
    size(): number;
    clear(): void;
}