fix(sandbox): fix TypeScript compilation error in disclosure.ts

The reveal() function was trying to return the result of setXP()
which returns void. Fixed by setting XP first, then returning
the threshold value.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.needle-predispatch-sha

@@ -1 +1 @@
-dff235e19318f50109a3f29edcd1f01b6cc94857
+164fcd225b8d5d0c6179bc1ea3c0ead92004efb3

web/src/lib/disclosure.ts

@@ -158,7 +158,8 @@ export function reveal(featureKey: string): number | null {
     return null;
   }
 
-  return setXP(feature.xpThreshold);
+  setXP(feature.xpThreshold);
+  return feature.xpThreshold;
 }
 
 /**