fix(cw): Enter sent nothing on the Icom/Yaesu/Kenwood keyers

Send-on-type keys each character as it is typed, which only the WinKeyer
and Flex CWX can do -- so the checkbox is shown for those two alone. The
stored preference, however, survives a change of engine: an operator who
had used it on a WinKeyer and moved to CI-V carried an invisible switch
that was still on.

The consequences fit the report exactly. Nothing keyed while typing,
because wkSendRaw falls through to the WinKeyer that is not there; and
Enter sent nothing either, because sendText believes the text has already
gone out. Macros take another path and kept working.

The panel now derives the flag from the engine rather than trusting the
stored value.

frontend/src/components/WinkeyerPanel.tsx

@@ -73,9 +73,17 @@ export function WinkeyerPanel({
 
   const connected = status.connected;
 
+  // Send-on-type only exists where the engine can key one character at a time:
+  // the WinKeyer and Flex CWX. The stored preference survives an engine change,
+  // though, and an Icom or Yaesu operator inherited a hidden switch that was on
+  // — the checkbox is not shown for them, so nothing keyed as they typed AND
+  // Enter sent nothing either, since it believes the text has already gone.
+  // Macros kept working, which is exactly how it looked from the outside.
+  const liveType = sendOnType && (source === 'winkeyer' || source === 'flex');
+
   function sendText() {
     const t = cwText.trim();
-    if (t && !sendOnType) onSend(t); // in send-on-type the text already went out
+    if (t && !liveType) onSend(t); // in send-on-type the text already went out
     setCwText('');
   }
 
@@ -83,7 +91,7 @@ export function WinkeyerPanel({
   // WinKeyer backspace for each deleted char (removes it from the buffer if it
   // hasn't been keyed yet). Only end-of-string edits are mirrored live.
   function onCwChange(v: string) {
-    if (sendOnType && connected) {
+    if (liveType && connected) {
       const old = cwText;
       if (v.length > old.length && v.startsWith(old)) {
         onSendRaw(v.slice(old.length));
@@ -200,13 +208,13 @@ export function WinkeyerPanel({
               value={cwText}
               onChange={(e) => onCwChange(e.target.value)}
               onKeyDown={(e) => { if (e.key === 'Enter') { e.preventDefault(); sendText(); } }}
-              placeholder={sendOnType ? t('wkp.phLive') : t('wkp.phEnter')}
+              placeholder={liveType ? t('wkp.phLive') : t('wkp.phEnter')}
               disabled={!connected}
               className="font-mono uppercase"
             />
           </div>
           <Button size="sm" className="h-8" onClick={sendText} disabled={!connected}>
-            <Send className="size-3.5" /> {sendOnType ? t('wkp.clear') : t('wkp.send')}
+            <Send className="size-3.5" /> {liveType ? t('wkp.clear') : t('wkp.send')}
           </Button>
           <Button variant="destructive" size="sm" className="h-8" onClick={onStop} disabled={!connected} title={t('wkp.abort')}>
             <Square className="size-3.5" /> {t('wkp.stop')}