export declare function formatThoughtSummary(durationMs: number, charCount: number): string;
export declare class ThinkingLane {
    private buffer;
    private startedAt;
    private endedAt;
    private hasEmitted;
    private committedUpTo;
    push(chunk: string): void;
    markEnded(): void;
    isActive(): boolean;
    hasBufferedContent(): boolean;
    peek(): string;
    consume(): string;
    peekPhase(): string;
    drainPhase(): string;
    collapse(): string | null;
    inlineSummary(): string | null;
}