feat: improve dark mode contrast in Tower3D and IsolatedRoof3D components

app/src/lib/theme.tsx

@@ -61,4 +61,24 @@ export function useTheme(): ThemeContextValue {
   const ctx = useContext(ThemeContext);
   if (!ctx) throw new Error('useTheme deve ser usado dentro de ThemeProvider');
   return ctx;
+}
+
+export function useCanvasTheme(): 'light' | 'dark' {
+  const [isDark, setIsDark] = useState(() => {
+    if (typeof document === 'undefined') return false;
+    return document.documentElement.classList.contains('dark');
+  });
+
+  useEffect(() => {
+    const observer = new MutationObserver(() => {
+      setIsDark(document.documentElement.classList.contains('dark'));
+    });
+    observer.observe(document.documentElement, {
+      attributes: true,
+      attributeFilter: ['class'],
+    });
+    return () => observer.disconnect();
+  }, []);
+
+  return isDark ? 'dark' : 'light';
 }