fix: replace emoji flags with text badges, clean city names from postal codes

Emoji flags render as boxes on Linux. Replace with a small FR/BE/CH
badge. Also strip postal codes from Cesium+ city names (e.g.
"Saint-Jean-de-Laur, 46260" → "Saint-Jean-de-Laur").

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/StatsPanel.tsx

@@ -1,6 +1,5 @@
 import { useRef } from 'react';
 import type { PeriodStats } from '../services/DataService';
-import { countryCodeToFlag } from '../services/adapters/CesiumAdapter';
 
 interface StatsPanelProps {
   stats: PeriodStats | null;
@@ -121,8 +120,13 @@ export function StatsPanel({ stats, loading, periodDays, source }: StatsPanelPro
             >
               <span className="text-base">{MEDALS[i]}</span>
               <div className="flex-1 min-w-0">
-                <p className="text-white text-sm font-medium truncate">
-                  {countryCodeToFlag(city.countryCode)}{city.countryCode ? ' ' : ''}{city.name}
+                <p className="text-white text-sm font-medium truncate flex items-center gap-1.5">
+                  {city.countryCode && (
+                    <span className="shrink-0 text-[10px] font-bold bg-[#1e1f2a] text-[#6b7280] rounded px-1 py-0.5 leading-none">
+                      {city.countryCode}
+                    </span>
+                  )}
+                  {city.name}
                 </p>
                 <p className="text-[#6b7280] text-xs">{city.count} tx</p>
               </div>