ThreadManagerTest:
  ✓ Constructor creates thread manager
  ✓ createThread returns thread_id and private_key
  ✓ createThread accepts metadata
  ✓ Thread stores metadata correctly
  ✓ threadExists returns true for existing thread
  ✓ threadExists returns false for non-existent thread
  ✓ getThread returns thread data
  ✓ updateThreadActivity updates last_activity timestamp
  ✓ incrementThreadStats updates statistics
  ✓ Thread statistics are correctly incremented
  ✓ verifyPrivateKey accepts correct key
  ✓ verifyPrivateKey rejects incorrect key
  ✓ listThreads returns array of threads
  ✓ getStatistics returns comprehensive statistics
  ✓ deleteThread removes thread and all data
  ✓ Deleted thread no longer exists
  ✓ cleanupExpiredThreads removes old threads