fix(watchlist): the auto-contest FIELD — the backend shipped without its UI

The wiring script died on an app.go anchor mid-run: the backend half was
committed, the frontend half (the pattern field, the changed-event refresh, the
i18n keys) never ran. Replayed; the field sits after Add.

frontend/src/components/WatchlistTab.tsx

@@ -20,7 +20,9 @@ import { useI18n } from '@/lib/i18n';
 import {
   WatchlistEntries, WatchlistAdd, WatchlistRemove, WatchlistSetNotify,
   WatchlistSetContest, WatchlistWorkedSlots,
+  GetWatchlistContestPattern, SetWatchlistContestPattern,
 } from '../../wailsjs/go/main/App';
+import { EventsOn } from '../../wailsjs/runtime/runtime';
 import type { ClusterSpot, SpotStatusEntry } from '@/components/ClusterGrid';
 import { inferSpotMode, spotStatusKey } from '@/lib/spot';
 
@@ -72,7 +74,18 @@ export function WatchlistTab({ spots, spotStatus, onSpotSelect, onSpotClick }: P
     try { setEntries(((await WatchlistEntries()) ?? []) as any as WLEntry[]); }
     catch (e: any) { setError(String(e?.message ?? e)); }
   }, []);
-  useEffect(() => { void refresh(); }, [refresh]);
+  // Refreshed on mount, when the backend auto-adds (event), and on a slow tick
+  // so last-seen and the spot counters stay honest while the tab sits open.
+  useEffect(() => {
+    void refresh();
+    const off = EventsOn('watchlist:changed', () => { void refresh(); });
+    const id = window.setInterval(() => { void refresh(); }, 30_000);
+    return () => { off(); window.clearInterval(id); };
+  }, [refresh]);
+  // The auto-contest pattern (DXHunter's contest_prefix): spots whose call
+  // contains it are added as contest entries by the backend.
+  const [pattern, setPattern] = useState('');
+  useEffect(() => { GetWatchlistContestPattern().then((p: string) => setPattern(p ?? '')).catch(() => {}); }, []);
 
   // Live spots per entry — prefix-matched, newest first, deduped per band+mode
   // (one line per slot; the freshest spot represents it).
@@ -191,6 +204,11 @@ export function WatchlistTab({ spots, spotStatus, onSpotSelect, onSpotClick }: P
         <Button size="sm" className="h-8" onClick={() => void add()} disabled={!addCall.trim()}>
           <Plus className="size-3.5" /> {t('wl.add')}
         </Button>
+        <Input className="h-8 w-28 font-mono uppercase" placeholder={t('wl.patternPh')}
+          title={t('wl.patternHint')}
+          value={pattern}
+          onChange={(e) => setPattern(e.target.value.toUpperCase())}
+          onBlur={() => { void SetWatchlistContestPattern(pattern.trim()); }} />
         <div className="flex-1" />
         <div className="relative">
           <Search className="size-3.5 absolute left-2 top-1/2 -translate-y-1/2 text-muted-foreground" />