/**
 * @fileoverview Mermaid zoom-stage guardian (v2.5.12 / Task #2951).
 *
 * Why this module exists
 * ----------------------
 * The Mermaid controller (`public/mermaid-renderer.js`) wraps every
 * freshly-rendered SVG in a `.mermaid-zoom-stage` div that carries
 * the pan/zoom CSS transform and the pointer-drag handlers. Without
 * that wrapper the user can neither pan nor zoom the lifecycle
 * diagram.
 *
 * Mermaid's library auto-runs `mermaid.run({nodes})` once
 * `startOnLoad: true` is set in `mermaid.initialize`. We DO set
 * `startOnLoad: true` in the SSR template (server.ts line ~2041) so
 * the initial paint works for hosts that don't ship our controller.
 * The auto-runner scans the DOM for `.mermaid` elements that are not
 * already marked `data-processed` and replaces their innerHTML with a
 * freshly-rendered SVG.
 *
 * Even after our controller's `update()` has set `data-processed="true"`
 * and wrapped the SVG, Mermaid's auto-runner fires roughly 1.5–3s
 * later (observed via Playwright trace on 2026-08-12) and replaces
 * the contents of the `.mermaid` element with a fresh, bare SVG. The
 * bare SVG is not wrapped in `.mermaid-zoom-stage`, so the pan/zoom
 * UI silently breaks for the rest of the page lifetime.
 *
 * What this module does
 * ---------------------
 * `ensureMermaidZoomStage(container)` — one-shot helper that walks
 * the container and wraps any existing `<svg>` in a
 * `.mermaid-zoom-stage` div. Idempotent: calling it twice keeps ONE
 * wrapper.
 *
 * `MermaidZoomGuardian` — a long-lived `MutationObserver` that
 * detects when something (Mermaid's late `mermaid.run()`, an SSE
 * patch, etc.) replaces the SVG and re-applies the wrapper. The
 * guardian stops observing after `stop()` is called.
 *
 * Both helpers are deliberately framework-free so they can be unit-
 * tested in happy-dom / jsdom without a full browser.
 */
/**
 * Wrap any existing SVG inside `container` in a single
 * `.mermaid-zoom-stage` div. Idempotent.
 *
 * @returns the (possibly newly-created) stage element, or `null`
 *          when the container has no SVG to wrap.
 */
export declare function ensureMermaidZoomStage(container: Element): HTMLElement | null;
/**
 * v2.5.12 (Task #2951): the MermaidZoomGuardian watches a container
 * and re-wraps any replacement SVG in `.mermaid-zoom-stage`. Use
 * this for diagrams that survive past the initial render — e.g. the
 * lifecycle mermaid on the per-task page, where Mermaid's late
 * `mermaid.run()` otherwise destroys the wrapper.
 *
 * Lifecycle:
 *   const g = new MermaidZoomGuardian(container);
 *   g.start();
 *   // ...later, when the page is torn down:
 *   g.stop();
 */
export declare class MermaidZoomGuardian {
    private readonly container;
    private observer;
    private scheduled;
    constructor(container: Element);
    start(): void;
    stop(): void;
}
/**
 * Export the constants so tests can reference them without hardcoding.
 */
export declare const MERMAID_STAGE_CLASS = "mermaid-zoom-stage";
export declare const MERMAID_TOOLBAR_CLASS = "mermaid-zoom-toolbar";
export declare const MERMAID_CONTAINER_CLASS = "mermaid";
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