v0.1.20

Fixed - Camera entities not appearing

• Fix camera entity creation — the camera platform setup was blocking
  for up to 60s with a retry loop, causing HA to cancel the setup
  coroutine before periodic discovery was registered
• Fix deprecated HA timer API — use properly imported
  async_track_time_interval instead of deprecated hass.helpers.event
  proxy which silently failed in modern HA
• 30-second discovery polling — cameras are now discovered via a
  non-blocking 30s polling interval, so entities appear quickly even if
  the addon isn't ready at startup