fix: restrict RST fields to valid report values

The RST comboboxes allowed free text, so a report typed by hand that isn't in
the mode's list (e.g. "600") was committed. Drop allowFreeText on the four RST
fields (QSO entry + edit modal) and make commit-on-type push a value only when
it's actually in the list; a leftover invalid entry reverts to the last valid
value on blur. Programmatically filled values (FT8 SNR over UDP, presets) are
unaffected — only manual typing is constrained.

frontend/src/App.tsx

@@ -2879,12 +2879,12 @@ export default function App() {
   );
   const rstTxBlock = (
     <div className="flex flex-col w-20"><Label className="mb-1 h-3.5">{t('field.rstTx')}</Label>
-      <Combobox value={rstSent} options={rstOptions(mode, rstLists)} allowFreeText commitOnType onChange={(v) => { setRstSent(v); rstUserEditedRef.current = true; }} />
+      <Combobox value={rstSent} options={rstOptions(mode, rstLists)} commitOnType onChange={(v) => { setRstSent(v); rstUserEditedRef.current = true; }} />
     </div>
   );
   const rstRxBlock = (
     <div className="flex flex-col w-20"><Label className="mb-1 h-3.5">{t('field.rstRx')}</Label>
-      <Combobox value={rstRcvd} options={rstOptions(mode, rstLists)} allowFreeText commitOnType onChange={(v) => { setRstRcvd(v); rstUserEditedRef.current = true; }} />
+      <Combobox value={rstRcvd} options={rstOptions(mode, rstLists)} commitOnType onChange={(v) => { setRstRcvd(v); rstUserEditedRef.current = true; }} />
     </div>
   );
   // DX country flag, shown large next to RST (moved here from the Country field).

frontend/src/components/QSOEditModal.tsx

@@ -412,9 +412,9 @@ export function QSOEditModal({ qso, onSave, onDelete, onClose, countries = [], b
                     value={draft.callsign ?? ''} onChange={(e) => set('callsign', e.target.value)} />
                 </div>
                 <div className="flex flex-col w-20"><Label>S</Label>
-                  <Combobox value={draft.rst_sent ?? ''} options={rstOptions(draft.mode ?? '', rstLists)} allowFreeText commitOnType onChange={(v) => set('rst_sent', v)} /></div>
+                  <Combobox value={draft.rst_sent ?? ''} options={rstOptions(draft.mode ?? '', rstLists)} commitOnType onChange={(v) => set('rst_sent', v)} /></div>
                 <div className="flex flex-col w-20"><Label>R</Label>
-                  <Combobox value={draft.rst_rcvd ?? ''} options={rstOptions(draft.mode ?? '', rstLists)} allowFreeText commitOnType onChange={(v) => set('rst_rcvd', v)} /></div>
+                  <Combobox value={draft.rst_rcvd ?? ''} options={rstOptions(draft.mode ?? '', rstLists)} commitOnType onChange={(v) => set('rst_rcvd', v)} /></div>
                 <Button type="button" variant="outline" className="h-10" onClick={fetchLookup} disabled={looking}
                   title={t('qedit.fetchTitle')}>
                   {looking ? <Loader2 className="size-4 animate-spin" /> : <Search className="size-4" />} {t('qedit.fetch')}

frontend/src/components/ui/combobox.tsx

@@ -64,7 +64,17 @@ export function Combobox({
         // Focus selects the text so a keystroke replaces it — but does NOT
         // open the list (so tabbing in doesn't pop the dropdown).
         onFocus={(e) => { setQuery(value); e.currentTarget.select(); }}
-        onChange={(e) => { setQuery(e.target.value); setOpen(true); if (commitOnType) onChange(e.target.value); }}
+        onChange={(e) => {
+          const v = e.target.value;
+          setQuery(v);
+          setOpen(true);
+          // Commit-on-type pushes the value live to the parent (so a CW macro sent
+          // without leaving the field uses what was just typed). With free text that's
+          // any input; a restricted field (allowFreeText=false) commits ONLY a value
+          // that's actually in the list, so a half-typed or invalid report never
+          // becomes the committed value — blur then reverts the leftover text.
+          if (commitOnType && (allowFreeText || options.some((o) => o.toLowerCase() === v.trim().toLowerCase()))) onChange(v);
+        }}
         onBlur={onBlur}
         onKeyDown={(e) => {
           if ((e.key === 'ArrowDown' || e.key === 'Alt') && !open) { setOpen(true); }