v0.45.2

[mqtt5 0.45.2] - 2026-10-02

Fixed

• A cancelled publish() no longer keeps a Receive Maximum slot (part of #168). A QoS 1 or 2 publish takes a send-quota slot before its message is stored as in flight. If the publish() future was dropped in between, for example by a timeout or a select! while it waited on a lock, the slot was never returned, and with a small Receive Maximum every later QoS 1 or 2 publish waited until the next reconnect. The slot is now returned when the future is dropped before the message is stored.