Move registerEventHandlers() call before the readLoop goroutine starts
in connectAndRun(). This eliminates the startup window where live gateway
events were actively read and dropped as 'unhandled' because handler
registration happened only after initialSync completed.
The handlers only depend on c.agents and c.broker, which are wired in the
constructor — they do not require initialSync to have completed.
Also adds TestConnectAndRun_EventNotLostDuringSync regression test that
sends a live presence event during initial sync and asserts it is not lost.
All gateway tests pass with -race.
rex-bot
b7b05bb4e3