fix(openstreetmap): use map.once('moveend') for reliable viewport sync

apps/client/src/botsu/openstreetmap/BotsuOpenStreetMap.tsx

@@ -13,6 +13,7 @@ type LeafletMap = {
   getCenter: () => { lat: number; lng: number };
   getZoom: () => number;
   on: (event: string, fn: () => void) => void;
+  once: (event: string, fn: () => void) => void;
   off: (event: string, fn: () => void) => void;
   remove: () => void;
 };
@@ -132,10 +133,10 @@ export function BotsuOpenStreetMap() {
       if (!map) return;
       syncingRef.current = true;
       map.setView([viewport.lat, viewport.lng], viewport.zoom);
-      // Reset syncing flag after animation (~300ms)
-      setTimeout(() => {
+      // Reset syncing flag only after the animation actually finishes
+      map.once('moveend', () => {
         syncingRef.current = false;
-      }, 300);
+      });
     });
   }, [mapViewportBridge]);