fix: resolve frontend lint errors and cleanup types

frontend/src/app/(protected)/layout.tsx

@@ -12,7 +12,7 @@ export default function ProtectedLayout({
   children: React.ReactNode;
 }) {
   const { data } = useSession();
-  const isAdmin = (data?.user as any)?.isAdmin;
+  const isAdmin = data?.user?.isAdmin;
 
   return (
     <AuthGuard>

frontend/src/app/(protected)/shifts/[id]/page.tsx

@@ -7,7 +7,6 @@ import { Button } from '@/components/ui/button';
 import { Progress } from '@/components/ui/progress';
 import { Badge } from '@/components/ui/badge';
 import { useRouter } from 'next/navigation';
-import { useSession } from 'next-auth/react';
 
 export default function ShiftDetailPage({ params }: { params: Promise<{ id: string }> }) {
   const resolvedParams = use(params);
@@ -15,7 +14,6 @@ export default function ShiftDetailPage({ params }: { params: Promise<{ id: stri
   const signUpMutation = useSignUpShift();
   const cancelMutation = useCancelSignUp();
   const router = useRouter();
-  const { data: session } = useSession();
 
   if (isLoading) return <div>Loading shift...</div>;
   if (!shift) return <div>Shift not found</div>;

frontend/src/auth/auth.ts

@@ -47,14 +47,14 @@ export const { handlers, signIn, signOut, auth } = NextAuth({
     async jwt({ token, account }) {
       if (account && account.access_token) {
         // Add clubs claim from Keycloak access token
-        token.clubs = (account as any).clubs as Record<string, string> || {}
-        token.accessToken = account.access_token as string
+        token.clubs = (account as { clubs?: Record<string, string> }).clubs || {}
+        token.accessToken = account.access_token
         
         try {
           const payload = JSON.parse(Buffer.from((token.accessToken as string).split('.')[1], 'base64').toString());
-          const roles = payload.realm_access?.roles || [];
+          const roles = (payload.realm_access?.roles as string[]) || [];
           token.isAdmin = roles.includes('admin');
-        } catch (e) {
+        } catch {
           token.isAdmin = false;
         }
       }
@@ -63,10 +63,10 @@ export const { handlers, signIn, signOut, auth } = NextAuth({
     async session({ session, token }) {
       // Expose clubs to client
       if (session.user) {
-        session.user.clubs = (token as any).clubs as Record<string, string> | undefined
-        session.user.isAdmin = (token as any).isAdmin as boolean | undefined
+        session.user.clubs = token.clubs as Record<string, string> | undefined
+        session.user.isAdmin = token.isAdmin as boolean | undefined
       }
-      session.accessToken = (token as any).accessToken as string | undefined
+      session.accessToken = token.accessToken as string | undefined
       return session
     }
   }

frontend/src/components/admin/club-management.tsx

@@ -17,10 +17,11 @@ export function ClubManagement() {
   const [isCreating, setIsCreating] = useState(false);
   const [newClub, setNewClub] = useState({ name: '', sportType: 'Tennis', description: '' });
 
-  const fetchClubs = async () => {
+  useEffect(() => {
+    const fetchClubsLocally = async () => {
       try {
         const res = await fetch(`${process.env.NEXT_PUBLIC_API_URL}/api/admin/clubs`, {
-        headers: { Authorization: `Bearer ${(session as any)?.accessToken}` },
+          headers: { Authorization: `Bearer ${session?.accessToken}` },
         });
         if (res.ok) {
           const data = await res.json();
@@ -33,10 +34,25 @@ export function ClubManagement() {
       }
     };
 
-  useEffect(() => {
-    if (session) fetchClubs();
+    if (session) fetchClubsLocally();
   }, [session]);
 
+  const fetchClubs = async () => {
+    try {
+      const res = await fetch(`${process.env.NEXT_PUBLIC_API_URL}/api/admin/clubs`, {
+        headers: { Authorization: `Bearer ${session?.accessToken}` },
+      });
+      if (res.ok) {
+        const data = await res.json();
+        setClubs(data);
+      }
+    } catch (error) {
+      console.error('Failed to fetch clubs', error);
+    } finally {
+      setLoading(false);
+    }
+  };
+
   const handleCreate = async (e: React.FormEvent) => {
     e.preventDefault();
     try {
@@ -44,7 +60,7 @@ export function ClubManagement() {
         method: 'POST',
         headers: {
           'Content-Type': 'application/json',
-          Authorization: `Bearer ${(session as any)?.accessToken}`,
+          Authorization: `Bearer ${session?.accessToken}`,
         },
         body: JSON.stringify({
           name: newClub.name,
@@ -67,7 +83,7 @@ export function ClubManagement() {
     try {
       const res = await fetch(`${process.env.NEXT_PUBLIC_API_URL}/api/admin/clubs/${id}`, {
         method: 'DELETE',
-        headers: { Authorization: `Bearer ${(session as any)?.accessToken}` },
+        headers: { Authorization: `Bearer ${session?.accessToken}` },
       });
       if (res.ok) {
         fetchClubs();

frontend/src/components/auth-guard.tsx

@@ -18,7 +18,7 @@ export function AuthGuard({ children }: { children: ReactNode }) {
 
   useEffect(() => {
     if (status === 'authenticated') {
-      const isAdmin = (data?.user as any)?.isAdmin;
+      const isAdmin = data?.user?.isAdmin;
       
       // Admin routing
       if (isAdmin) {
@@ -59,7 +59,7 @@ export function AuthGuard({ children }: { children: ReactNode }) {
     );
   }
 
-  const isAdmin = (data?.user as any)?.isAdmin;
+  const isAdmin = data?.user?.isAdmin;
   if (clubs.length === 0 && status === 'authenticated' && !isAdmin) {
     const handleSwitchAccount = () => {
       const keycloakLogoutUrl = `${process.env.NEXT_PUBLIC_KEYCLOAK_ISSUER || 'http://localhost:8080/realms/workclub'}/protocol/openid-connect/logout?redirect_uri=${encodeURIComponent(window.location.origin + '/login')}`;