chore: sample the Yaesu meters throughout a transmission, not at its start

The one-shot survey fired as the transmission began and caught the meters still
at rest — RM4=13 and everything else zero, which identifies nothing. And the
operator's reading points the other way: the bar showing 81 tracks his 100 W,
while the one labelled power sat at 8.

What names a meter is which index FOLLOWS the power over a few seconds of steady
carrier, so the survey now samples on every poll while transmitting, capped at a
dozen lines. Two seconds of tune will settle it.

Still not guessing at the mapping: the numbers will say which index is power and
which is SWR on this radio, and it gets corrected then.

internal/cat/yaesu.go

@@ -104,8 +104,9 @@ type Yaesu struct {
 	panelLoaded bool
 	// Commands this rig answered "?;" to — asked once, then never again.
 	unsupported map[string]bool
-	// metersSurveyed: the one-shot RM1..RM6 dump during the first transmission.
-	metersSurveyed bool
+	// metersLogged counts the RM1..RM6 samples taken during transmission, so the
+	// survey follows a real carrier instead of catching one instant of it.
+	metersLogged int
 }
 
 func NewYaesu(portName string, baud int, digital string) *Yaesu {