fix: heatmap overlay — masque les snapshots pendant zoom/pan, resync après

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

src/components/HeatMap.tsx

@@ -63,7 +63,40 @@ export function HeatMap({ transactions }: HeatMapProps) {
     mapRef.current = map;
     heatRef.current = heat;
 
+    // Pendant zoom/pan : cache les overlays → le canvas live est visible directement.
+    // Après zoom/pan : resynchronise le snapshot sur le canvas redesssiné.
+    const hideOverlays = () => {
+      const prev = prevRef.current;
+      const next = nextRef.current;
+      if (prev) { prev.style.transition = 'none'; prev.style.opacity = '0'; }
+      if (next) { next.style.transition = 'none'; next.style.opacity = '0'; }
+      currentSrcRef.current = '';
+    };
+
+    const syncAfterMove = () => {
+      const canvas = (heat as unknown as { _canvas?: HTMLCanvasElement })._canvas;
+      const next = nextRef.current;
+      if (!canvas || !next) return;
+      // Double RAF : leaflet.heat redessine en interne après l'événement
+      requestAnimationFrame(() => {
+        requestAnimationFrame(() => {
+          try {
+            const src = canvas.toDataURL();
+            currentSrcRef.current = src;
+            next.src = src;
+            next.style.transition = 'none';
+            next.style.opacity = '1';
+          } catch { /* map torn down */ }
+        });
+      });
+    };
+
+    map.on('zoomstart movestart', hideOverlays);
+    map.on('zoomend moveend', syncAfterMove);
+
     return () => {
+      map.off('zoomstart movestart', hideOverlays);
+      map.off('zoomend moveend', syncAfterMove);
       map.remove();
       mapRef.current = null;
       heatRef.current = null;