fix(onboarding): prevent invisible overlay blocking clicks and stuck tour

- Tie spotlight/tooltip pointer-events to isVisible so opacity:0 stops
  trapping taps during step transitions
- Render target click-catcher only when overlay is fully visible and
  clear stale targetRect on step change
- Retry target lookup up to 6 times and auto-skip step (or complete
  tour) when target is missing, instead of leaving overlay stuck
  invisible-but-interactive
- Persist completion to localStorage before unmounting the tour, so
  the flag survives even if unmount throws

src/pages/Dashboard.tsx

@@ -246,8 +246,8 @@ export default function Dashboard() {
   }, [t, subscription]);
 
   const handleOnboardingComplete = () => {
-    setShowOnboarding(false);
     completeOnboarding();
+    setShowOnboarding(false);
   };
 
   return (