feat: record CW QSOs again

CW was excluded because SmartSDR does not route the operator's own sidetone
through DAX, so the recording sounds one-sided. The audio path is open all the
same and the other station IS captured — which is the half worth keeping.

The frontend had ONE list serving two purposes: which modes may be recorded, and
which modes the voice keyer may transmit on. Adding CW to it would have let the
DVK key the rig with speech on a CW frequency. They are now two lists: PHONE_MODES
for the keyer, RECORDABLE_MODES (phone + CW) for the recorder.

Digital modes stay out of both: their audio is a modem tone nobody will replay.

frontend/src/App.tsx

@@ -137,7 +137,15 @@ const DEFAULT_MODES = ['SSB','CW','FT8','FT4','RTTY','PSK31','AM','FM','DIGITALV
 // Modes the QSO recorder captures (phone only). Mirrors recordableMode() in
 // app.go — digital modes carry no useful audio, and CW has no DAX audio on Flex,
 // so neither is recorded (no REC badge / timer for them).
-const RECORDABLE_MODES = new Set(['SSB','USB','LSB','AM','FM','DV']);
+// Modes a VOICE keyer may transmit on. Not a recording list — the DVK plays
+// speech, and sending it on CW or a data slot keys the rig with a human voice.
+const PHONE_MODES = new Set(['SSB','USB','LSB','AM','FM','DV']);
+
+// Modes worth recording. Phone, plus CW: the audio path stays open in CW, so
+// the other station's signal is captured. Your own sidetone is not in it —
+// SmartSDR does not route it through DAX — and that is accepted. Digital modes
+// stay out: their audio is a modem tone nobody will ever replay.
+const RECORDABLE_MODES = new Set([...PHONE_MODES, 'CW']);
 
 const emptyDetails: DetailsState = {
   state: '', cnty: '', address: '',
@@ -1233,7 +1241,7 @@ export default function App() {
   useEffect(() => { dvkAutoCqSecsRef.current = dvkAutoCqSecs; localStorage.setItem('opslog.dvkAutoCqSecs', String(dvkAutoCqSecs)); }, [dvkAutoCqSecs]);
   // The DVK is a VOICE keyer — transmitting it on CW/FT8/RTTY would key the rig
   // with speech on a data slot. Only allow it on phone modes.
-  const isPhoneMode = (m: string) => RECORDABLE_MODES.has((m || '').toUpperCase());
+  const isPhoneMode = (m: string) => PHONE_MODES.has((m || '').toUpperCase());
   const modeRef = useRef(mode);
   useEffect(() => { modeRef.current = mode; }, [mode]);
   function stopDvkAutoCq() { dvkAutoCqSlotRef.current = -1; dvkAutoCqGenRef.current++; }