v8.1.0

Bug Fixes

• Fix MQTT connection flapping after reconnect: When _active_reconnect()
  created a new MqttConnection, the old connection was never closed. The old
  SDK connection's built-in auto-reconnect would eventually succeed, creating two
  active connections sharing the same client ID. Because AWS IoT allows only one
  connection per client ID, the broker would kick one off, triggering
  on_connection_interrupted and starting yet another reconnection — an
  infinite connect/disconnect loop. Fixed by adding MqttConnection.close()
  (unconditional teardown regardless of _connected state) and calling it
  before creating the replacement connection in both _active_reconnect() and
  _deep_reconnect().

• Thread-safety race in ensure_device_info_cached: The future.done()
  check and future.set_result() were performed in the AWS SDK callback thread
  without synchronisation, creating a race against the asyncio event loop thread.
  Moved both operations inside a call_soon_threadsafe callback so they execute
  atomically on the event loop thread.

• ZeroDivisionError when deep_reconnect_threshold is 0: Config validation
  now clamps deep_reconnect_threshold to a minimum of 1, preventing a
  ZeroDivisionError in the exponential-backoff reconnection logic.

• Reconnect counter never incremented: total_reconnect_attempts in
  diagnostics was not incremented on connection drops, so it always reported 0
  despite active reconnections. Counter is now incremented on each
  on_connection_interrupted event.

• shortest_session_seconds not JSON-serialisable: The diagnostics
  to_dict() method used float('inf') as the initial value for
  shortest_session_seconds, which is not valid JSON. Changed to None
  so serialisation succeeds when no session has completed yet.

• wait_for() future not bound to running loop: wait_for() created a
  bare asyncio.Future() rather than
  asyncio.get_running_loop().create_future(), which could bind the future to
  a different loop in multi-loop test setups.

• Reservation temperature validation was US-only: build_reservation_entry
  validated set-point temperatures against hardcoded Fahrenheit bounds (95–150 °F)
  regardless of the active unit system. Validation now uses the current unit system
  context: 35–65 °C in metric mode, 95–150 °F in US mode. Celsius users previously
  received spurious ValueError rejections for valid temperatures.

• Malformed reservation data silently dropped: build_reservation_entry now
  logs a warning when reservation hex data contains unexpected trailing bytes
  instead of silently dropping partial entries.

• Unknown PeriodicRequestType silently ignored: The periodic-request handler
  now logs an error and breaks when it encounters an unknown request type instead of
  doing nothing.

• Memory leak in device info cache: get_all_cached() only filtered expired
  entries from its return value but left them in the cache dictionary. Expired
  entries are now evicted during get_all_cached() to prevent unbounded growth.