fix(ui-patterns): restore userCode dependency in test-reset useEffect

The biome auto-formatter removed userCode from the useEffect dependency
array, which broke the "reset test results when code changes" behavior.
Add biome-ignore comment to preserve the intentional trigger dependency.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: davidagustin

app/frontend-drills/[framework]/ui-patterns/[patternId]/page.tsx

@@ -853,9 +853,10 @@ export default function UIPatternDetail() {
   }, []);
 
   // Reset test results when user code changes
+  // biome-ignore lint/correctness/useExhaustiveDependencies: intentionally re-run on userCode change
   useEffect(() => {
     setTestResults(null); // eslint-disable-line react-hooks/set-state-in-effect -- Reset tests on code change
-  }, []);
+  }, [userCode]);
 
   const handleRunTests = useCallback(() => {
     if (previewIframeRef.current?.contentWindow) {