fix(tci): TUNE can be switched off again, and the meters watch it

Two faults with one cause: this radio does not echo 'tune:0,true'.

So the panel never knew a tune was running. The button stayed on TUNE and
every further press sent another START — there was no way to stop it from
here at all. The state is recorded when the command is sent now; whatever
the radio says afterwards still wins, it simply never says anything.

And the transmit meters were asked for only while t.tx, which a tune
carrier does not set: the radio reports tuning as its own state, not as a
transmission. So power and SWR sat at zero for the whole tune — the exact
carrier an operator holds a tune for in order to watch an SWR on. They now
follow PTT or TUNE, and the S-meter reads '—' under our own carrier
either way.

frontend/src/components/TCIPanel.tsx

@@ -274,15 +274,15 @@ export function TCIPanel({ onReportRST }: { onReportRST?: (rst: string) => void
             There is no temperature: the protocol has no such command, and a
             made-up figure on a transmitter is the kind somebody trusts. */}
         <Card icon={Activity} title={t('tcip.meters')}>
-          <MeterBar label="S-METER" value={st.tx ? 0 : sBar(st.smeter)} lo={0} hi={100}
+          <MeterBar label="S-METER" value={st.tx || st.tuning ? 0 : sBar(st.smeter)} lo={0} hi={100}
             accent="#16a34a" segColor={sSegColor}
-            display={st.tx ? '—' : `${s.label}  ${st.smeter} dBm`}
+            display={st.tx || st.tuning ? '—' : `${s.label}  ${st.smeter} dBm`}
             onClick={() => {
               if (st.tx || !onReportRST) return;
               onReportRST(sMeterRST(s.s, s.over, mode));
             }}
             title={t('tcip.sMeterHint')} />
-          {st.tx && (
+          {(st.tx || st.tuning) && (
             <div className="grid grid-cols-1 sm:grid-cols-2 gap-2">
               <MeterBar label="PWR" value={st.tx_power_w} lo={0} hi={Math.max(10, Math.ceil(st.tx_power_w / 10) * 10)}
                 accent="#0ea5e9" display={`${st.tx_power_w.toFixed(1)} W`} />