Merge remote-tracking branch 'origin/rf_emulator_and_timers_fix' into integration_2025_w34 (!3589)

RF emulator and improvements of the timers

RF emulator:
Add an RF library emulating a real device without the need of a real
device.  This is thought to enable using phy-test without requiring a
radio device or channel simulation.  The library synchronizes on the
real time clock, drops TX and generate noise on RX.  Noise generation
can be disabled and the noise level configured.

Timers improvements:
- Fix standard deviation for merged timers
- Add display of ULSCH decoding timers
- Add decoding timer in AAL

common/utils/time_meas.h

@@ -193,6 +193,7 @@ static inline void merge_meas(time_stats_t *dst_ts, const time_stats_t *src_ts)
     return;
   dst_ts->trials += src_ts->trials;
   dst_ts->diff += src_ts->diff;
+  dst_ts->diff_square += src_ts->diff_square;
   if (src_ts->max > dst_ts->max)
     dst_ts->max = src_ts->max;
 }