v0.2.1rc1

Pre-release - for testing

A real PEP 440 pre-release: pip install pybluetti will not pick this up. Test with:

pip install pybluetti==0.2.1rc1

Fixed

• _run() was leaving the abandoned websocket connection open on every exit path except a token-expiry (msgCode 805) - an ApplicationRuntimeException, a plain ERROR/CLOSE message, or an unexpected crash all skipped close(). This let a concurrently-running heartbeat send slip past its own is-it-closed check and fail against the transport, reported as Failed to send heartbeat: Cannot write to closing transport repeating on every ~30s reconnect cycle - confirmed in production on 0.2.0 itself, via bluetti-official/bluetti-home-assistant#145. _run() now closes the connection itself as soon as it decides to abandon it.

See the CHANGELOG for the full technical writeup.