In-Place TTY Spinner (util/spinner.ts)

Redraws one status line in place while work runs, then erases it so scrollback stays clean. Methods no-op off a TTY so captured logs stay untouched. Reuse for CLI progress indicators.

// Source: https://github.com/trailhq/Trail-Code | License: MIT | Copyright 2026 Context Graph Engine contributors
// Provided via justclaw.it.com; keep this notice with the code.
/**
 * One line that redraws in place while something runs, and is erased when it
 * stops — so nothing interactive is left in the scrollback.
 *
 * Only on a TTY. Anywhere else every method is a no-op, and the caller prints
 * whatever finished lines it wants a log to keep.
 */
const FRAMES = ["⠋", "⠙", "⠹", "⠸", "⠼", "⠴", "⠦", "⠧", "⠇", "⠏"];

export interface Spinner {
  /** Change the text after the frame. */
  update(text: string): void;
  /** Print a finished line above the spinner, which keeps spinning below it. */
  print(line: string): void;
  /** Erase the line and stop. Safe to call more than once. */


... (truncated -- full source via MCP)