fix: prevent admin page reload redirect to dashboard

Wait for admin role check to complete before setting loading to false.
This prevents race condition where:
1. authLoading becomes false after session loads
2. isAdmin is still false (async check in progress)
3. Page redirects to /dashboard before isAdmin is set to true

Now loading stays true until BOTH session and admin role are loaded,
ensuring admin pages don't redirect on reload.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/hooks/useAuth.tsx

@@ -31,11 +31,14 @@ export function AuthProvider({ children }: { children: ReactNode }) {
       setUser(session?.user ?? null);
 
       if (session?.user) {
-        checkAdminRole(session.user.id);
+        // Wait for admin role check before setting loading to false
+        checkAdminRole(session.user.id).then(() => {
+          if (mounted) setLoading(false);
+        });
+      } else {
+        // No session, set loading to false immediately
+        if (mounted) setLoading(false);
       }
-
-      // Only set loading to false after initial session is loaded
-      setLoading(false);
     });
 
     // Then listen for auth state changes
@@ -47,13 +50,15 @@ export function AuthProvider({ children }: { children: ReactNode }) {
         setUser(session?.user ?? null);
 
         if (session?.user) {
-          checkAdminRole(session.user.id);
+          // Wait for admin role check
+          checkAdminRole(session.user.id).then(() => {
+            if (mounted) setLoading(false);
+          });
         } else {
           setIsAdmin(false);
+          // No session, set loading to false immediately
+          if (mounted) setLoading(false);
         }
-
-        // Ensure loading is false after auth state changes
-        setLoading(false);
       }
     );
 
@@ -70,8 +75,9 @@ export function AuthProvider({ children }: { children: ReactNode }) {
       .eq('user_id', userId)
       .eq('role', 'admin')
       .maybeSingle();
-    
+
     setIsAdmin(!!data);
+    return !!data; // Return the result
   };
 
   const signIn = async (email: string, password: string) => {