Fix NodeJS.Timeout type errors in frontend

- Change NodeJS.Timeout to ReturnType<typeof setTimeout> for browser compatibility
- Fix timeout ref types in GovernanceModelBadge and TeamDashboard
- All TypeScript compilation errors now resolved

frontend/src/components/GovernanceModelBadge.tsx

@@ -54,7 +54,7 @@ export default function GovernanceModelBadge({
   className = '',
 }: GovernanceModelBadgeProps) {
   const [isHovered, setIsHovered] = useState(false);
-  const hoverTimeoutRef = useRef<NodeJS.Timeout | null>(null);
+  const hoverTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   const badgeRef = useRef<HTMLDivElement>(null);
 
   const style = getGovernanceModelStyle(governanceModelName);

frontend/src/components/TeamDashboard.tsx

@@ -68,7 +68,7 @@ export default function TeamDashboard() {
   const [statusDropdownOpen, setStatusDropdownOpen] = useState(false);
   const [governanceModels, setGovernanceModels] = useState<ReferenceValue[]>([]);
   const [hoveredGovModel, setHoveredGovModel] = useState<string | null>(null);
-  const hoverTimeoutRef = useRef<NodeJS.Timeout | null>(null);
+  const hoverTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);
 
   // Hover handlers with delayed hide to prevent flickering when moving between badges
   const handleGovModelMouseEnter = useCallback((hoverKey: string) => {

frontend/src/types/node.d.ts

@@ -1,4 +1,5 @@
 // Type definitions for Node.js types used in frontend
+// In browser context, setTimeout returns number, not NodeJS.Timeout
 declare namespace NodeJS {
-  interface Timeout {}
+  interface Timeout extends ReturnType<typeof setTimeout> {}
 }