fix: validate OAuth configuration before starting the flow

src/components/MCPServerManager.tsx

@@ -312,12 +312,17 @@ export const MCPServerManager: React.FC<MCPServerManagerProps> = ({
                         const endpoints = await discoverOAuthEndpoints(
                           newServer.url
                         );
+                        
+                        if (!endpoints.clientId || !endpoints.redirectUri) {
+                          throw new Error("Missing required OAuth configuration (clientId or redirectUri)");
+                        }
+                        
                         startOAuthFlow({
                           authorizationEndpoint:
                             endpoints.authorizationEndpoint,
-                          clientId: endpoints.clientId,
-                          redirectUri: endpoints.redirectUri,
-                          scopes: endpoints.scopes,
+                          clientId: endpoints.clientId as string,
+                          redirectUri: endpoints.redirectUri as string,
+                          scopes: (endpoints.scopes || []) as string[],
                         });
                       } catch (err) {
                         setNotification({