Function memoryHeader

src/utils/attachments.ts:2385–2390

(path: string, mtimeMs: number)

 * can fall back for resumed sessions where the stored header is missing.
 */
export function memoryHeader(path: string, mtimeMs: number): string {
  const staleness = memoryFreshnessText(mtimeMs)
  return staleness
    ? `${staleness}\n\nMemory: ${path}:`
    : `Memory (saved ${memoryAge(mtimeMs)}): ${path}:`
}

/**
 * A memory relevance-selector prefetch handle. The promise is started once