/**
 * Build `snapshotHintsJson` for `setupSeedChannel` (bare_os.snapshot_hints RPC → booter proc).
 * @param {Record<string, string | undefined> | null | undefined} hostEnv
 * @returns {string}
 */
export function buildSeederSnapshotHintsJson(hostEnv) {
  const e = hostEnv && typeof hostEnv === 'object' ? hostEnv : {}
  const explicit = String(e.BARE_OS_SEED_SNAPSHOT_HINTS_JSON ?? '').trim()
  if (explicit) return explicit
  const tag = String(e.BARE_OS_SEED_CORESTORE_SNAPSHOT_TAG ?? '').trim()
  if (!tag) return ''
  return JSON.stringify({
    schema: 1,
    corestoreSnapshotTag: tag,
    source: 'BARE_OS_SEED_CORESTORE_SNAPSHOT_TAG'
  })
}