RegistryManagerTest:
  ✓ Constructor without parameters
  ✓ Constructor with thread context
  ✓ buildRegistriesFromBlocks extracts layouts
  ✓ buildRegistriesFromBlocks extracts word blocks
  ✓ getLayoutsToProcess identifies unprocessed layouts
  ✓ mapPIIToWordBlocks maps PII to word blocks
  ✓ applyPIIToPage returns PII blocks for page
  ✓ saveCachedRegistry saves data to cache
  ✓ loadCachedRegistry loads cached data
  ✓ getStatistics returns comprehensive statistics
  ✓ clearCache removes cached data
  ✓ Cache is empty after clearing