feat(cluster): chase switches for POTA and SOTA

An operator who does not chase parks does not want NEW POTA shouting from every
activator spot. Two switches (Settings → DX Cluster, on by default): off, the
marker is withdrawn at the display layer — applySpotDisplay, the same chokepoint
the grid, the band map and the filter read through — so the badge, the colour,
the filter chip and the reference column all go quiet together, and a new-band +
new-POTA spot reads NEW BAND alone. The facts keep being computed; only the
telling stops, so ticking the box back on needs no rescan.

frontend/src/components/SettingsModal.tsx

@@ -2068,6 +2068,8 @@ function SettingsModalImpl({ onClose, onSaved, initialSection, onMainPaneChanged
     try { await SaveGridScopeSettings(next); } catch { /* the panel keeps the choice either way */ }
   };
   const [chaseGrids, setChaseGrids] = useState(false);
+  const [chasePotaOn, setChasePotaOn] = useState(() => localStorage.getItem('opslog.chasePota') !== '0');
+  const [chaseSotaOn, setChaseSotaOn] = useState(() => localStorage.getItem('opslog.chaseSota') !== '0');
   const [chaseNew, setChaseNew] = useState(false);
   const [spotTTL, setSpotTTL] = useState(0);
   const [spotTTLText, setSpotTTLText] = useState('0');
@@ -5380,6 +5382,19 @@ function SettingsModalImpl({ onClose, onSaved, initialSection, onMainPaneChanged
           </div>
 
           <div className="border-t border-border/60 pt-3 space-y-2">
+            {/* Chase switches: off, the marker stops being TOLD, everywhere at
+                once — badge, colour, filter chip, reference column. A "new band
+                + new POTA" spot then reads NEW BAND alone. */}
+            <label className="flex items-center gap-2 text-sm cursor-pointer" title={t('clu.chasePotaHint')}>
+              <Checkbox checked={chasePotaOn}
+                onCheckedChange={(c) => { const v = !!c; setChasePotaOn(v); writeUiPref('opslog.chasePota', v ? '1' : '0'); }} />
+              {t('clu.chasePota')}
+            </label>
+            <label className="flex items-center gap-2 text-sm cursor-pointer" title={t('clu.chaseSotaHint')}>
+              <Checkbox checked={chaseSotaOn}
+                onCheckedChange={(c) => { const v = !!c; setChaseSotaOn(v); writeUiPref('opslog.chaseSota', v ? '1' : '0'); }} />
+              {t('clu.chaseSota')}
+            </label>
             <label className="flex items-start gap-2 text-sm cursor-pointer">
               <Checkbox checked={chaseGrids} className="mt-0.5"
                 onCheckedChange={(c) => { setChaseGrids(!!c); SetChaseNewGrids(!!c).catch(() => {}); }} />