/**
 * Live queue display — a bottom-anchored input box that stays visible
 * during streaming and tool execution, so the user can see what they're
 * typing into the queue (and erase it with backspace).
 *
 * The technique: ANSI DECSTBM (Set Top and Bottom Margins) reserves a
 * scrolling region above the last row. Streaming output scrolls in the
 * upper region; the bottom row is fixed and we redraw it on every
 * keystroke.
 *
 * Layout:
 *
 *   ┌── upper scroll region (rows 1..N-1) ──┐
 *   │                                        │
 *   │  streamed model output writes here     │
 *   │  scrolling naturally as text arrives   │
 *   │                                        │
 *   ├── fixed bottom row (row N) ────────────┤
 *   │  ▶ queued: <user's typed text>         │  ← updated on each keystroke
 *   └────────────────────────────────────────┘
 *
 * Caveats:
 *   - DECSTBM is widely supported (xterm, iTerm, Windows Terminal,
 *     Alacritty, Kitty) but legacy ConHost has quirks. If activation
 *     fails or the terminal isn't a TTY, we no-op.
 *   - Terminal resize mid-stream isn't handled — the box stays at the
 *     row we reserved. Acceptable trade-off; resize is rare mid-chain.
 *   - Screen-reader mode skips this entirely — NVDA / JAWS read every
 *     cursor move as fresh text, which makes a live-updating widget
 *     much worse than a quiet one-line hint.
 */
/**
 * Begin reserving the bottom row + setting the scroll region.
 * Safe to call repeatedly; subsequent calls are no-ops.
 * Returns true if activation succeeded.
 */
export declare function activate(): boolean;
/**
 * Update the input-box content. Call on every typed char (or
 * backspace) so the user sees their queue in real time.
 *
 * Truncates text to fit terminal width; if longer, shows the LAST
 * (cols-12) chars so the most-recent typing is always visible.
 */
export declare function update(text: string): void;
/**
 * Tear down the box and restore the default scroll region.
 * Safe to call repeatedly; no-op when not active.
 *
 * Idempotency matters because we want this in `finally` blocks alongside
 * other cleanup that might also call it.
 */
export declare function deactivate(): void;
/** Test helper / fallback: are we currently active? */
export declare function isActive(): boolean;