fix: improve service worker offline flow and dev toggle UX

src/components/ui/NetworkStatus.tsx

@@ -9,7 +9,7 @@ export function NetworkStatus() {
   if (isOnline) return null;
 
   return (
-    <div className="fixed bottom-4 left-4 z-[100] flex items-center gap-2 rounded-lg bg-destructive/90 backdrop-blur-md px-4 py-2 text-sm text-destructive-foreground shadow-lg">
+    <div className="fixed right-4 top-[calc(4.5rem+env(safe-area-inset-top,0px))] z-[110] flex items-center gap-2 rounded-full border border-destructive/40 bg-destructive/90 px-3 py-1.5 text-xs font-semibold uppercase tracking-wide text-destructive-foreground shadow-lg backdrop-blur-md animate-in fade-in slide-in-from-top-1">
       <WifiOff className="h-4 w-4" />
       <span>Hors ligne</span>
     </div>