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marker is withdrawn at the display layer — applySpotDisplay, the same chokepoint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/App.tsx

@@ -98,7 +98,7 @@ import { ExportFieldsDialog } from '@/components/ExportFieldsDialog';
 import { ShutdownProgress } from '@/components/ShutdownProgress';
 import { ClusterGrid } from '@/components/ClusterGrid';
 import { cleanSpotter, inferSpotMode, spotModeCategory, spotStatusKey } from '@/lib/spot';
-import { applySpotDisplay, readSpotDisplayOptions, spotIsWorked, SPOT_DISPLAY_OPTIONS_EXPOSED } from '@/lib/spotDisplay';
+import { applySpotDisplay, chasePota, readSpotDisplayOptions, spotIsWorked, SPOT_DISPLAY_OPTIONS_EXPOSED } from '@/lib/spotDisplay';
 import { AnswerDecode, HaltDecodeTx, LogUIError, FlexTXOnBand, GetMatrixColors, GetRotorPresets, GetRowColors, GetSpotTTLMinutes, GetSpotMax, IsNewUSCounty } from '../wailsjs/go/main/App';
 import { applyMatrixColors } from '@/lib/matrixColors';
 import { WorkedBeforeGrid } from '@/components/WorkedBeforeGrid';
@@ -6127,7 +6127,8 @@ export default function App() {
               // worked spots; the separate "Hide worked" checkbox drops them — they
               // are opposite controls, so don't use both at once.
               { k: 'worked'   as SpotFilterKey, label: 'WORKED',   cls: 'bg-info-muted text-info-muted-foreground border-info-border' },
-            ]).map((s: any) => fChip(s.k, s.label, s.cls, clusterStatusFilter.has(s.k),
+            ]).filter((s: any) => s.k !== 'new-pota' || chasePota())
+              .map((s: any) => fChip(s.k, s.label, s.cls, clusterStatusFilter.has(s.k),
               () => setClusterStatusFilter((cur) => { const n = new Set(cur); if (n.has(s.k)) n.delete(s.k); else n.add(s.k); return n; }), s.style))}
           </div>,
           clusterStatusFilter.size > 0 ? (