fix(cluster): NEW CALL is not NEW SLOT

The slot-highlight option reused the new-slot status, which already meant
something else and something narrower: the ENTITY was worked on this band and
on this mode, but never on the two together. What the option surfaces is a fact
about the CALLSIGN - never worked on this band and mode - and the entity may be
long since confirmed there.

Overloading it cost exactly what it always costs. Forty consecutive rows read
NEW SLOT, the genuine new-slot rows drowned in them, and the Status column
stopped carrying information at all.

new-call is its own status now, with its own badge, its own tooltip spelling out
that it is the callsign and not the entity, and its own filter chip. It keeps
the caution colour for the moment: it sits at the same "worth a look, not a new
one" level as new-slot, and the colour rework will separate them.

The status filter had to move onto the displayed status too. It read the raw
backend entry, where new-call by construction never appears, so the chip would
have selected nothing at all.

frontend/src/components/BandMap.tsx

@@ -158,6 +158,7 @@ function statusLabel(s: string, t: (k: string) => string, muted = false): string
     case 'new-band': return t('bmp.statusNewBand');
     case 'new-mode': return t('bmp.statusNewMode');
     case 'new-slot': return t('bmp.statusNewSlot');
+    case 'new-call': return t('bmp.statusNewCall');
     case 'worked':   return t('bmp.statusWorked');
     // An empty status means the entity could not be resolved — EXCEPT when the
     // "no colour on worked stations" option emptied it on purpose. Saying
@@ -201,6 +202,7 @@ function statusStyle(s: string, muted = false): { pill: string; bar: string; lin
       line: 'stroke-warning',
       dot:  'fill-warning',
     };
+    case 'new-call':
     case 'new-slot': return {
       pill: 'bg-caution-muted text-caution-muted-foreground border-caution-border hover:bg-caution-muted',
       bar:  'bg-caution',
@@ -320,6 +322,7 @@ export function BandMap({ band, spots, spotStatus: spotStatusRaw, currentFreqHz,
         case 'new':      return 0;
         case 'new-band': return 1;
         case 'new-slot': return 2;
+        case 'new-call': return 2;
         case 'worked':   return 4;
         default:         return 3;
       }