v0.3.44

feat(comms): add 7s TX watchdog to force FT4 PTT off (#26)

_TxWorker's done.wait() previously had no timeout, so PTT-off was
entirely gated on the audio stream's own completion signal -- if that
signal is delayed (the CAT-traffic/GIL stall this issue is about) or
never arrives, the rig stays keyed with no automatic recovery short of
the operator noticing and pressing Halt TX. Adds a 7.0s ceiling (under
one FT4 T/R period, 7.5s): if the audio thread hasn't signalled done by
then, abort the stream exactly as Halt TX would and proceed to the
existing unconditional PTT-off, surfaced as an error (not "TX done") so
it's visible when it fires. Independent of whatever the underlying
stretch turns out to be.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>