Function stickyPromptText

src/components/VirtualMessageList.tsx:133–144

(msg: RenderableMessage)

 */
const promptTextCache = new WeakMap<RenderableMessage, string | null>();
function stickyPromptText(msg: RenderableMessage): string | null {
  // Cache keyed on message object — messages are append-only and don't
  // mutate, so a WeakMap hit is always valid. The walk (StickyTracker,
  // per-scroll-tick) calls this 5-50+ times with the SAME messages every
  // tick; the system-reminder strip allocates a fresh string on each
  // parse. WeakMap self-GCs on compaction/clear (messages[] replaced).
  const cached = promptTextCache.get(msg);
  if (cached !== undefined) return cached;
  const result = computeStickyPromptText(msg);
  promptTextCache.set(msg, result);
  return result;
}
function computeStickyPromptText(msg: RenderableMessage): string | null {
  let raw: string | null = null;
  if (msg.type === 'user') {