Fetch all station polygons without limit

Removed the .slice(0, 30) limit on polygon fetches. All stations with
position data now get their polygons fetched in parallel. This was
causing Florida stations (rank 31+) to be missing from longer time
windows where more European stations pushed them past the cutoff.

Also sort by messagesWithPosition descending so stations with the
richest polygon data are fetched first.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: kevinelliott

map/src/components/map/CoverageMap.tsx

@@ -110,14 +110,16 @@ export default function CoverageMap() {
   const fetchPolygons = useCallback(async () => {
     const MARINE_TYPES = new Set(['aiscatcher', 'ais']);
 
-    const withPosition = stations.filter((s) => {
-      if (s.latitude === 0 && s.longitude === 0) return false;
-      if (s.messagesWithPosition <= 0) return false;
-      // Transport filter
-      if (transportFilter === 'aircraft' && MARINE_TYPES.has(s.sourceType)) return false;
-      if (transportFilter === 'marine' && !MARINE_TYPES.has(s.sourceType)) return false;
-      return true;
-    }).slice(0, 30);
+    const withPosition = stations
+      .filter((s) => {
+        if (s.latitude === 0 && s.longitude === 0) return false;
+        if (s.messagesWithPosition <= 0) return false;
+        if (transportFilter === 'aircraft' && MARINE_TYPES.has(s.sourceType)) return false;
+        if (transportFilter === 'marine' && !MARINE_TYPES.has(s.sourceType)) return false;
+        return true;
+      })
+      // Sort by messagesWithPosition so stations with most polygon data are fetched first
+      .sort((a, b) => b.messagesWithPosition - a.messagesWithPosition);
 
     const polygons: CoveragePolygon[] = [];