style(cluster): give NEW SLOT its own colour

The whole new-* family shared the warning amber while the NEW PFX marker sits in
caution yellow — two different facts, two near-identical colours in one cell.
NEW SLOT now takes aqua (chart-2), the same story the panadapter palette already
tells: its default for new-slot has been cyan all along.

frontend/src/components/ClusterGrid.tsx

@@ -148,6 +148,11 @@ function statusFor(p: any): SpotStatusEntry | undefined {
 //   filled pfx  → new prefix  filled POTA → new park    filled county → new county
 //   blue call   → already worked (not a novelty, so text only)
 const NEW = 'var(--warning)'; // yellow: something here is new
+// NEW SLOT gets its own hue. It shared the amber NEW family while the NEW PFX
+// marker sits in caution yellow — two different facts, two near-identical
+// colours in the same cell. Aqua matches the cyan the panadapter palette
+// already gives new-slot, so the two views tell the story in the same colour.
+const NEWSLOT = 'var(--chart-2)';
 const WKD = 'var(--info)';    // blue: this callsign is already in the log
 
 // FILLING the cell that carries the fact, rather than only tinting its text.
@@ -190,9 +195,10 @@ function statusColor(s: SpotStatusEntry | undefined): string | null {
     case 'new-band-mode':
     case 'new-band':
     case 'new-mode':
-    case 'new-slot':
     case 'new-call':
       return NEW;
+    case 'new-slot':
+      return NEWSLOT;
     default:
       return s?.worked_call ? WKD : null;
   }