fix(frontend): resolve TypeScript errors in TracePage

- Fix if-else missing semicolon (TS1005)
- Fix useRef missing initial value (TS2554)

frontend/web/src/pages/admin/TracePage.tsx

@@ -23,7 +23,7 @@ export default function TracePage() {
   const [traces, setTraces] = useState<any[]>([])
   const [expanded, setExpanded] = useState<Set<string>>(new Set())
   const [selected, setSelected] = useState<any>(null)
-  const intervalRef = useRef<number>()
+  const intervalRef = useRef<number>(0)
 
   useEffect(() => {
     fetchTraces()
@@ -42,7 +42,7 @@ export default function TracePage() {
 
   const toggleExpand = (id: string) => {
     const next = new Set(expanded)
-    if (next.has(id)) next.delete(id) else next.add(id)
+    if (next.has(id)) next.delete(id); else next.add(id)
     setExpanded(next)
   }