/**
 * Serializes Mermaid work behind a single promise tail.
 *
 * This exists because Mermaid is effectively a singleton in-process:
 * `mermaid.initialize()` mutates shared config, `getDiagramFromText()` and
 * `render()` use shared internal state, and `render()` also inserts temporary
 * DOM nodes while it works. If those operations overlap, callers can race on
 * config, parser state, and transient DOM.
 *
 * The returned promise preserves the caller's real result or error. The
 * internal queue tail is normalized back to `Promise<void>` so a failed task
 * does not poison the queue or leave the queue state holding an unhandled
 * rejection.
 */
export declare const runMermaidTaskSequentially: <T>(task: () => Promise<T>) => Promise<T>;