Release 0.5.2

Fixed

• Transient failures talking to the Telegram collector (e.g.
  ConnectionResetError(104, 'Connection reset by peer'), refused
  connections, timeouts, 5xx responses) now retry automatically up to
  three times with exponential backoff before any exception bubbles up.
  If all retries fail (or the upstream returns a non-retryable error
  like 4xx), the run logs a single ERROR line and exits with status
  3 instead of dumping a traceback — cron-friendly behaviour.