v0.3.42

feat(rig): log satmode CAT set_freq() call duration (#26)

Diagnostic for the still-open FT4/Q65 TX "stretched transmission"
symptom on IC-9700 satmode Direct rigs. Hamlib's Python (SWIG) binding
is built without -threads (unlike SoapySDR's), so each DL/UL
set_freq() call holds the GIL for its whole blocking CAT round-trip.
During TX, _tracking_through_tx()'s 1 Hz UL threshold can turn this
into near-continuous CAT traffic — suspected of starving _TxWorker's
PortAudio callback thread and causing the reported output underflow.
Times each satmode DL/UL set_freq() call directly and logs it
(WARNING at >=80ms) so a reproduction can be compared against
ft4_decode.log's existing "tx callback_stats" for the same session.

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