fix: resolve TypeScript errors in migrated components

apps/web/src/components/gantt/GanttChart.tsx

@@ -215,7 +215,7 @@ export function GanttChart({
   onTaskClick,
   height = 400,
   showDependencies = false,
-}: GanttChartProps): JSX.Element {
+}: GanttChartProps): React.ReactElement {
   // Sort tasks by start date
   const sortedTasks = useMemo(() => {
     return [...tasks].sort((a, b) => a.startDate.getTime() - b.startDate.getTime());